US5709745A
Expired / Lapsed
US
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Compound semi-conductors and controlled doping thereof
Assignee: Ohio Aerospace Institute
•
Filing: 1995-11-06
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Granted: 1998-01-20
•
Expires: 2015-11-06
Abstract
Abstract A method of controlling the amount of impurity incorporation in a crystal grown by a chemical vapor deposition process. Conducted in a growth chamber, the method includes the controlling of the concentration of the crystal growing components in the growth chamber to affect the demand of particular growth sites within the growing crystal thereby controlling impurity incorporation into the growth sites.
Inventors
- 👤 David J. Larkin
- 👤 Philip G. Neudeck
- 👤 J. Anthony Powell
- 👤 Lawrence G. Matus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:28
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/20; H10P14/34; H10P14/3402; H10P14/3404; H10P14/3408; C; C30; C30B; C30B25/00; C30B25/02; C30B25/18; C30B29/00; C30B29/10; C30B29/36; H10P14/24; H10P14/29; H10P14/2901; H10P14/2902; H10P14/2904; H10P14/2907; H10P14/2911; H10P14/3414; H10P14/3421; H10P14/3438; H10P14/3441; H10P14/3442; H10P14/3444; Y; Y10; Y10S; Y10S438/00; Y10S438/914; Y10S438/925
Claims Analysis
Total Claims: 59
Claim 1
Independent Claim
315 words
A method of regulating an amount of at least one non-crystal element deposited in a given growth area of a single crystal formed from at least two crystal elements as said crystal is grown in a growth chamber, said crystal elements comprising a first crystal element and a second crystal element, said crystal having at least two crystal growing sites wherein said first crystal element is deposited in a first growth site and said second crystal element is deposited in a second element growth site, said at least one non-crystal element being competitive for said first site, said method comprising the steps of: a. selecting an amount of said non-crystal element to be deposited in said given growth area; b. selecting a ratio of said first crystal element to said second crystal element, said ratio being dependent on said selected amount of said non-crystal element to be deposited in said given growth area; c. flowing a controlled amount of at least one gaseous crystal element compound through said chamber to grow said crystal, said controlled amount corresponding to said selected ratio of said first crystal element to said second crystal element in said growth chamber, and each of said element compound including at least one of said crystal element; d. selecting a new amount of said non-crystal element to be deposited in said given growth area; e. selecting a new ratio of said first crystal element to said second crystal element to obtain said new amount of said non-crystal element to be deposited in said given growth area; and, f. changing said ratio of said crystal elements in said growth chamber during the growing of said crystal to regulate said amount of said at least one non-crystal element deposited in said competitive crystal growth site at said growth area to obtain said new amount of said non-crystal element being deposited in said given growth area.
Claim 2
Independent Claim
315 words
A method of regulating an amount of at least one non-crystal element deposited in a given growth area of a single crystal formed from at least two crystal elements as said crystal is grown in a growth chamber, said crystal elements comprising a first crystal element and a second crystal element, said crystal having at least two crystal growing sites wherein said first crystal element is deposited in a first growth site and said second crystal element is deposited in a second element growth site, said at least one non-crystal element being competitive for said first site, said method comprising the steps of: a. selecting an amount of said non-crystal element to be deposited in said given growth area; b. selecting a ratio of said first crystal element to said second crystal element, said ratio being dependent on said selected amount of said non-crystal element to be deposited in said given growth area; c. flowing a controlled amount of at least one gaseous crystal element compound through said chamber to grow said crystal, said controlled amount corresponding to said selected ratio of said first crystal element to said second crystal element in said growth chamber, and each of said element compound including at least one of said crystal element; d. selecting a new amount of said non-crystal element to be deposited in said given growth area; e. selecting a new ratio of said first crystal element to said second crystal element to obtain said new amount of said non-crystal element to be deposited in said given growth area; and, f. changing said ratio of said crystal elements in said growth chamber during the growing of said crystal to regulate said amount of said at least one non-crystal element deposited in said competitive crystal growth site at said growth area to obtain said new amount of said non-crystal element being deposited in said given growth area.
Claim 3
Dependent Claim
42 words
A method as defined in claim 1, including a step of changing the amount of said at least one non-crystal element being deposited in said first growth site by changing said ratio of said second crystal element to said first crystal element.
Claim 4
Dependent Claim
17 words
A method as defined in claim 2, wherein said at least one non-crystal element is a dopant.
Claim 5
Dependent Claim
25 words
A method as defined in claim 3, including a step of pre-treating said growth area to remove sites for heterogeneous nucleation during said crystal growth.
Claim 6
Dependent Claim
17 words
A method as defined in claim 4, wherein said pre-treating includes pregrowth etching of said growth area.
Claim 7
Dependent Claim
15 words
A method as defined in claim 4, wherein said pre-treating includes polishing said growth area.
Claim 8
Dependent Claim
20 words
A method as defined in claim 4, wherein said SiC crystal is grown on the growth area of a substrate.
Claim 9
Dependent Claim
21 words
A method as defined in claim 7, including a step of nucleating on said substrate to grow a particular crystal polytype.
Claim 10
Dependent Claim
31 words
A method as defined in claim 8, wherein said nucleating of said substrate is the introduction of an impurity at said site to stimulate the growth of a desired crystal structure.
Claim 11
Dependent Claim
22 words
A method as defined in claim 9, wherein said nucleating of said substrate is positioned in a corner of said growth area.
Claim 12
Dependent Claim
23 words
A method as defined in claim 7, wherein said growth area of said substrate has a non-zero inclination relative to a basal plane.
Claim 13
Dependent Claim
17 words
A method as defined in claim 11, wherein said non-zero inclination is greater than about seven degrees.
Claim 14
Dependent Claim
31 words
A method as defined in claim 11, including a step of dividing said growth area into growth regions defined by boundaries by introducing grooves along the boundaries of said growth regions.
Claim 15
Dependent Claim
23 words
A method as defined in claim 7, wherein said growth area of said substrate has a zero inclination relative to a basal plane.
Claim 16
Dependent Claim
19 words
A method as defined in claim 1, wherein said growth chamber is heated to a temperature of 800-2200° C.
Claim 17
Dependent Claim
29 words
A method as defined in claim 1, including a step of using a non-reactive carrier gas to introduce at least one of said crystal elements into said growth chamber.
Claim 18
Dependent Claim
14 words
A method as defined in claim 1, wherein said crystal is an SIC crystal.
Claim 19
Independent Claim
147 words
A method of growing crystals containing a non-crystal element, of a concentration of less than about 1.0×10 16 cm -3 , said crystal formed from at least two crystal elements being grown by a process conducted in a growth chamber, said crystal having at least two growth sites and said non-crystal element competitive for a growth site, said method comprising: a) identifying said growth site said non-crystal element is competitive for; b) identifying the crystal element which deposits in said growth site said non-crystal element is competitive for; c) selecting a crystal element ratio of said two crystal elements which contains an amount of the competing crystal element which will compete with said non-crystal element during said crystal growth to form said crystal with said selected amount of non-crystal element; and d) flowing said selected amount of crystal elements into said growth chamber to grow said crystal.
Claim 20
Independent Claim
147 words
A method of growing crystals containing a non-crystal element, of a concentration of less than about 1.0×10 16 cm -3 , said crystal formed from at least two crystal elements being grown by a process conducted in a growth chamber, said crystal having at least two growth sites and said non-crystal element competitive for a growth site, said method comprising: a) identifying said growth site said non-crystal element is competitive for; b) identifying the crystal element which deposits in said growth site said non-crystal element is competitive for; c) selecting a crystal element ratio of said two crystal elements which contains an amount of the competing crystal element which will compete with said non-crystal element during said crystal growth to form said crystal with said selected amount of non-crystal element; and d) flowing said selected amount of crystal elements into said growth chamber to grow said crystal.
Claim 21
Dependent Claim
32 words
A method as defined in claim 18, wherein said crystal element ratio is selected to form a crystal having a non-crystal element concentration of less than about 5.0×10 15 cm -3 .
Claim 22
Dependent Claim
21 words
A method as defined in claim 19, wherein said non-crystal element concentration of less than about 1.0×10 15 cm -3 .
Claim 23
Dependent Claim
32 words
A method as defined in claim 20, wherein said crystal element ratio is selected to form a crystal having a non-crystal element concentration of less than about 8.0×10 13 cm -3 .
Claim 24
Dependent Claim
67 words
A method as defined in claim 21, including a step of selecting a second concentration of said non-crystal element; selecting a new crystal element ratio to form said crystal with said second concentration of said non-crystal element; and changing said crystal element ratio to said new crystal element ratio during the growing of said crystal to form a crystal having multiple selected concentrations of said non-crystal element.
Claim 25
Dependent Claim
14 words
A method as defined in claim 18, wherein said crystal is an SIC crystal.
Claim 26
Independent Claim
142 words
A method containing a non-crystal element concentration of greater than about 1×10 19 cm -3 , said crystal formed from at least two crystal elements being grown by a process conducted in a growth chamber, said crystal having at least two growth sites and said non-crystal element competitive for a growth site, said method comprising: a) identifying said growth site said non-crystal element is competitive for; b) identifying the crystal element which deposits in said growth site said non-crystal element is competitive for; c) selecting a crystal element ratio of said two crystal elements which contains an amount of the competing crystal element which will compete with said non-crystal element during said crystal growth to form said crystal with said selected amount of non-crystal element; and d) flowing said selected amount of crystal elements into said growth chamber to grow said crystal.
Claim 27
Independent Claim
142 words
A method containing a non-crystal element concentration of greater than about 1×10 19 cm -3 , said crystal formed from at least two crystal elements being grown by a process conducted in a growth chamber, said crystal having at least two growth sites and said non-crystal element competitive for a growth site, said method comprising: a) identifying said growth site said non-crystal element is competitive for; b) identifying the crystal element which deposits in said growth site said non-crystal element is competitive for; c) selecting a crystal element ratio of said two crystal elements which contains an amount of the competing crystal element which will compete with said non-crystal element during said crystal growth to form said crystal with said selected amount of non-crystal element; and d) flowing said selected amount of crystal elements into said growth chamber to grow said crystal.
Claim 28
Dependent Claim
32 words
A method as defined in claim 24, wherein said crystal element ratio is selected to form a crystal having a non-crystal element concentration is greater than about 3.0×10 19 cm -3 .
Claim 29
Dependent Claim
32 words
A method as defined in claim 25, wherein said crystal element ratio is selected to form a crystal having a non-crystal element concentration is greater than about 5.0×10 19 cm -3 .
Claim 30
Dependent Claim
32 words
A method as defined in claim 26, wherein said crystal element ratio is selected to form a crystal having a non-crystal element concentration is greater than about 1.0×10 20 cm -3 .
Claim 31
Dependent Claim
32 words
A method as defined in claim 27, wherein said crystal element ratio is selected to form a crystal having a non-crystal element concentration is greater than about 5.0×10 20 cm -3 .
Claim 32
Dependent Claim
67 words
A method as defined in claim 27, including a step of selecting a second concentration of said non-crystal element; selecting a new crystal element ratio to form said crystal with said second concentration of said non-crystal element; and changing said crystal element ratio to said new crystal element ratio during the growing of said crystal to form a crystal having multiple selected concentrations of said non-crystal element.
Claim 33
Dependent Claim
67 words
A method as defined in claim 18, including a step of selecting a second concentration of said non-crystal element; selecting a new crystal element ratio to form said crystal with said second concentration of said non-crystal element; and changing said crystal element ratio to said new crystal element ratio during the growing of said crystal to form a crystal having multiple selected concentrations of said non-crystal element.
Claim 34
Dependent Claim
67 words
A method as defined in claim 24, including a step of selecting a second concentration of said non-crystal element; selecting a new crystal element ratio to form said crystal with said second concentration of said non-crystal element; and changing said crystal element ratio to said new crystal element ratio during the growing of said crystal to form a crystal having multiple selected concentrations of said non-crystal element.
Claim 35
Dependent Claim
14 words
A method as defined in claim 24, wherein said crystal is an SIC crystal.
Claim 36
Independent Claim
195 words
A method of growing a crystal containing a selected ratio of at least one n-type dopant and at least one p-type dopant, said crystal formed from at least two crystal elements being grown by a process conducted in a growth chamber, said crystal having at least two growth sites and said at least one n-type dopant primarily competitive for a n-type growth site and said at least one p-type dopant primarily competitive for a p-type growth site, said method comprising of: a) identifying said crystal element which primarily deposits in said p-type growth site; b) identifying said crystal element which primarily deposits in said n-type growth site; c) selecting said ratio of n-type dopant to said p-type dopant incorporation; d) selecting an element ratio which contains a certain amount of said n-type growth site crystal element to said p-type growth site crystal element to obtain said amount of n-type dopant and p-type dopant to be deposited in said crystal during crystal growth, said ratio being dependent on said selected ratio of said n-type to p-type dopant ratio; and e) flowing said at least two crystal elements into said growth chamber in said selected ratio amounts.
Claim 37
Independent Claim
195 words
A method of growing a crystal containing a selected ratio of at least one n-type dopant and at least one p-type dopant, said crystal formed from at least two crystal elements being grown by a process conducted in a growth chamber, said crystal having at least two growth sites and said at least one n-type dopant primarily competitive for a n-type growth site and said at least one p-type dopant primarily competitive for a p-type growth site, said method comprising of: a) identifying said crystal element which primarily deposits in said p-type growth site; b) identifying said crystal element which primarily deposits in said n-type growth site; c) selecting said ratio of n-type dopant to said p-type dopant incorporation; d) selecting an element ratio which contains a certain amount of said n-type growth site crystal element to said p-type growth site crystal element to obtain said amount of n-type dopant and p-type dopant to be deposited in said crystal during crystal growth, said ratio being dependent on said selected ratio of said n-type to p-type dopant ratio; and e) flowing said at least two crystal elements into said growth chamber in said selected ratio amounts.
Claim 38
Dependent Claim
14 words
A method as defined in claim 33, wherein said crystal is an SIC crystal.
Claim 39
Independent Claim
124 words
A method of growing single crystals containing a selected concentration of a non-crystal element, said single crystal formed from at least two crystal elements being grown by a process conducted in a growth chamber, said single crystal having at least two growth sites and said non-crystal element competitive for a growth site, said method comprising: a) identifying said growth site said non-crystal element is competitive for; b) identifying the crystal element which deposits in said growth site said non-crystal element is competitive for; c) controlling a crystal element ratio which contains a certain amount of the competing crystal element which will compete with said non-crystal element during said crystal growth so that ≳1.0×10 19 cm -3 of non-crystal element is incorporated in said crystal.
Claim 40
Independent Claim
124 words
A method of growing single crystals containing a selected concentration of a non-crystal element, said single crystal formed from at least two crystal elements being grown by a process conducted in a growth chamber, said single crystal having at least two growth sites and said non-crystal element competitive for a growth site, said method comprising: a) identifying said growth site said non-crystal element is competitive for; b) identifying the crystal element which deposits in said growth site said non-crystal element is competitive for; c) controlling a crystal element ratio which contains a certain amount of the competing crystal element which will compete with said non-crystal element during said crystal growth so that ≳1.0×10 19 cm -3 of non-crystal element is incorporated in said crystal.
Claim 41
Dependent Claim
14 words
A method as defined in claim 35, wherein said crystal is an SIC crystal.
Claim 42
Independent Claim
124 words
A method of growing single crystals containing a selected concentration of non-crystal element, said single crystal formed from at least two crystal elements being grown by a process conducted in a growth chamber, said single crystal having at least two growth sites and said non-crystal element competitive for a growth site, said method comprising: a) identifying said growth site said non-crystal element is competitive for; b) identifying the crystal growth which deposits in said growth site said non-crystal element is competitive for; c) controlling a crystal element ratio which contains a certain amount of the competing crystal element which will compete with said non-crystal element during said crystal growth so that ≲1.0×10 15 cm -3 of non-crystal element is incorporated in said single crystal.
Claim 43
Independent Claim
124 words
A method of growing single crystals containing a selected concentration of non-crystal element, said single crystal formed from at least two crystal elements being grown by a process conducted in a growth chamber, said single crystal having at least two growth sites and said non-crystal element competitive for a growth site, said method comprising: a) identifying said growth site said non-crystal element is competitive for; b) identifying the crystal growth which deposits in said growth site said non-crystal element is competitive for; c) controlling a crystal element ratio which contains a certain amount of the competing crystal element which will compete with said non-crystal element during said crystal growth so that ≲1.0×10 15 cm -3 of non-crystal element is incorporated in said single crystal.
Claim 44
Dependent Claim
14 words
A method as defined in claim 37, wherein said crystal is an SIC crystal.
Claim 45
Independent Claim
264 words
A method of selecting the amount of a dopant element deposited in a given growth area of a single crystal and reducing the amount of a contaminant element deposited in a given growth area of the single crystal, said single crystal formed from at least two crystal elements as said crystal is grown at an area by a CVD process conducted in a growth chamber, said crystal elements comprising a first crystal element and a second crystal element, said single crystal having at least two crystal growing sites wherein said first crystal element is deposited in a first growth site and said second crystal element is deposited in a second element growth site, said dopant element being competitive for at least one of said first and second growth sites, said contaminant element being competitive for a growth site other than said growth site of said dopant element, said method comprising the steps of: a) identifying said growth site said dopant element is competitive for; b) identifying said growth site said contaminant element is competitive for; c) identifying a first crystal element which deposits in said growth site said dopant element is competitive for; d) identifying a second crystal element which deposits in said growth side said contaminant element is competitive for; e) selecting a ratio of said two crystal elements to obtain said selected amount of said dopant element deposited in said competitive crystal growth site and simultaneously reducing said amount of said contaminant element deposited in said competitive crystal growth site; and f) flowing said selected ratio of crystal elements into said growth.
Claim 46
Independent Claim
264 words
A method of selecting the amount of a dopant element deposited in a given growth area of a single crystal and reducing the amount of a contaminant element deposited in a given growth area of the single crystal, said single crystal formed from at least two crystal elements as said crystal is grown at an area by a CVD process conducted in a growth chamber, said crystal elements comprising a first crystal element and a second crystal element, said single crystal having at least two crystal growing sites wherein said first crystal element is deposited in a first growth site and said second crystal element is deposited in a second element growth site, said dopant element being competitive for at least one of said first and second growth sites, said contaminant element being competitive for a growth site other than said growth site of said dopant element, said method comprising the steps of: a) identifying said growth site said dopant element is competitive for; b) identifying said growth site said contaminant element is competitive for; c) identifying a first crystal element which deposits in said growth site said dopant element is competitive for; d) identifying a second crystal element which deposits in said growth side said contaminant element is competitive for; e) selecting a ratio of said two crystal elements to obtain said selected amount of said dopant element deposited in said competitive crystal growth site and simultaneously reducing said amount of said contaminant element deposited in said competitive crystal growth site; and f) flowing said selected ratio of crystal elements into said growth.
Claim 47
Dependent Claim
37 words
A method as in claim 39, including a step of changing the rate of said dopant element deposited in said competitive growth site by changing said ratio of said crystal elements being flowed into said growth chamber.
Claim 48
Dependent Claim
31 words
A method as defined in claim 40, wherein said crystal element ratio is selected to produce a crystal containing a dopant element concentration of less than 1.0×10 16 cm -3 .
Claim 49
Dependent Claim
20 words
A method as defined in claim 41, wherein said dopant element concentration is less than 5.0×10 15 cm -3 .
Claim 50
Dependent Claim
30 words
A method as defined in claim 40, wherein said crystal element ratio is selected to produce a crystal containing a dopant element concentration of greater than 1.0×10.sup. cm -3 .
Claim 51
Dependent Claim
20 words
A method as defined in claim 43, wherein said dopant element concentration is greater than 5.0×10 19 cm -3 .
Claim 52
Dependent Claim
45 words
A method as defined in claim 40, including a step of varying at least once the ratio of said crystal elements being flowed into said growth chamber during the growing of said crystal to form a crystal having at least two different dopant element concentrations.
Claim 53
Dependent Claim
54 words
A method as defined in claim 45, including the step of adding a second dopant element to reduce incorporation of said contaminant element in said crystal, said second dopant element having the same electrical polarity as said dopant element and said second dopant competitive for said growth site said contaminant element is competitive for.
Claim 54
Dependent Claim
54 words
A method as defined in claim 46, including the step of adding a second dopant element to reduce incorporation of said contaminant element in said crystal, said second dopant element having the same electrical polarity as said dopant element and said second dopant competitive for said growth site said contaminant element is competitive for.
Claim 55
Dependent Claim
45 words
A method as defined in claim 39, including a step of varying at least once the ratio of said crystal element being flowed into said growth chamber during the growing of said crystal to form a crystal having at least two different dopant element concentrations.
Claim 56
Dependent Claim
54 words
A method as defined in claim 48, including the step of adding a second dopant element to reduce incorporation of said contaminant element in said crystal, said second dopant element having the same electrical polarity as said dopant element and said second dopant competitive for said growth site said contaminant element is competitive for.
Claim 57
Dependent Claim
54 words
A method as defined in claim 39, including a step of adding a second dopant element to reduce incorporation of said contaminant element in said crystal, said second dopant element having the same electrical polarity as said dopant element, and said second dopant competitive for said growth site said contaminant element is competitive for.
Claim 58
Dependent Claim
31 words
A method as defined in claim 50, including a step of increasing the flow rate of said second dopant to further reduce said amount of said contaminant incorporated in said crystal.
Claim 59
Dependent Claim
14 words
A method as defined in claim 39, wherein said crystal is an SIC crystal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2001-01-19 | 2001-07-21 | 2002-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-01-19 | 2005-07-21 | 2006-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-01-19 | 2009-07-21 | 2010-01-20 | $7700.00 | Window Closed / Lapsed |