Patent US966980A successfully refreshed from Google Patents.
Patent US5657335A successfully refreshed from Google Patents.
US5657335A
Expired / Lapsed
US
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P-type gallium nitride
Assignee: University of California
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Filing: 1993-11-01
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Granted: 1997-08-12
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Expires: 2013-11-01
Abstract
Abstract Several methods have been found to make p-type gallium nitride. P-type gallium nitride has long been sought for electronic devices. N-type gallium nitride is readily available. Discovery of p-type gallium nitride and the methods for making it will enable its use in ultraviolet and blue light-emitting diodes and lasers. pGaN will further enable blue photocathode elements to be made. Molecular beam epitaxy on substrates held at the proper temperatures, assisted by a nitrogen beam of the proper energy produced several types of p-type GaN with hole concentrations of about 5×10 11 /cm 3 and hole mobilities of about 500 cm 2 /V-sec, measured at 250° K. P-type GaN can be formed of unintentionally-doped material or can be doped with magnesium by diffusion, ion implantation, or co-evaporation. When applicable, the nitrogen can be substituted with other group III elements such as Al.
Inventors
- 👤 Michael Rubin
- 👤 Nathan Newman
- 👤 Tracy Fu
- 👤 Jennifer Ross
- 👤 James Chan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:48
CPC Classifications
H; H10; H10P; H10P30/00; H10P30/20; H10P30/21; H10H; H10H20/00; H10H20/01; H10H20/011; H10H20/013; H10H20/0133; H10H20/01335; H10H20/80; H10H20/81; H10H20/822; H10H20/824; H10H20/825; H10H20/8252; H10P30/202; H10P30/206; H10P30/28; H10P32/00; H10P32/10; H10P32/12; H10P32/17; H10P32/174
Claims Analysis
Total Claims: 60
Claim 1
Independent Claim
41 words
A chemical compound comprising near intrinsic III-V semiconductor wherein a) the V semiconductor comprises nitrogen; b) the III semiconductor comprises between 80% to 100% gallium; and c) charge carriers are primarily holes having a mobility between 40 cm2/Volt-sec and 600 cm2/Volt-sec.
Claim 2
Dependent Claim
41 words
A chemical compound comprising near intrinsic III-V semiconductor wherein a) the V semiconductor comprises nitrogen; b) the III semiconductor comprises between 80% to 100% gallium; and c) charge carriers are primarily holes having a mobility between 40 cm2/Volt-sec and 600 cm2/Volt-sec.
Claim 3
Dependent Claim
21 words
The chemical compound of claim 1 wherein hole concentration is between 10 10 cm -3 and 10 20 cm -3 .
Claim 4
Dependent Claim
21 words
The chemical compound of claim 2 wherein hole concentration is between 10 11 cm -3 and 10 19 cm -3 .
Claim 5
Dependent Claim
23 words
The chemical compound of claim 1 wherein between about 0 to about 10% of the gallium is replaced with other III semiconductor elements.
Claim 6
Dependent Claim
14 words
The chemical compound of claim 4 wherein the III semiconductor comprises gallium and aluminum.
Claim 7
Dependent Claim
43 words
A chemical compound comprising III-V semiconductor wherein a) the ratio of III semiconductor to nitrogen is between about 1.0:0.95 and stoichiometric b) the V semiconductor comprises nitrogen; c) the III semiconductor comprises at least 80% gallium; and d) charge carriers are primarily holes.
Claim 8
Dependent Claim
43 words
A chemical compound comprising III-V semiconductor wherein a) the ratio of III semiconductor to nitrogen is between about 1.0:0.95 and stoichiometric b) the V semiconductor comprises nitrogen; c) the III semiconductor comprises at least 80% gallium; and d) charge carriers are primarily holes.
Claim 9
Dependent Claim
17 words
The chemical compound of claim 6 wherein the ratio of III semiconductor to nitrogen is approximately stoichiometric.
Claim 10
Dependent Claim
15 words
The chemical compound of claim 6 wherein the III-V semiconductor is an unintentionally doped material.
Claim 11
Dependent Claim
15 words
The chemical compound of claim 6 wherein the III-V semiconductor is an intentionally doped material.
Claim 12
Dependent Claim
12 words
The chemical compound of claim 9 wherein the p-type dopant is magnesium.
Claim 13
Independent Claim
121 words
The method of making p-type GaN comprising, a. mounting a substrate on a heater; b. placing the heater and substrate in a vacuum chamber; c. biasing the substrate at a voltage sufficient to decelerate ions that approach its GaN growing surface; d. evacuating the chamber to a pressure low enough to operate a nitrogen source, mounted on or within the chamber; e. heating the substrate to a temperature between about 550° C. and about 900° C.; f. introducing nitrogen into the nitrogen source; g. extracting nitrogen ions into the chamber at the minimum energy allowed by the nitrogen source; j. depositing gallium onto the GaN growing surface at flux rate higher than the gallium desorbtion rate from the GaN growing surface.
Claim 14
Independent Claim
121 words
The method of making p-type GaN comprising, a. mounting a substrate on a heater; b. placing the heater and substrate in a vacuum chamber; c. biasing the substrate at a voltage sufficient to decelerate ions that approach its GaN growing surface; d. evacuating the chamber to a pressure low enough to operate a nitrogen source, mounted on or within the chamber; e. heating the substrate to a temperature between about 550° C. and about 900° C.; f. introducing nitrogen into the nitrogen source; g. extracting nitrogen ions into the chamber at the minimum energy allowed by the nitrogen source; j. depositing gallium onto the GaN growing surface at flux rate higher than the gallium desorbtion rate from the GaN growing surface.
Claim 15
Independent Claim
142 words
The method of making p-type GaN comprising, a. mounting a substrate on a heater; b. placing the heater and substrate in a vacuum chamber; c. biasing the substrate at a voltage sufficient to decelerate ions that approach its GaN growing surface; d. evacuating the chamber to a pressure low enough to operate an ion gun, mounted on or within the chamber; e. heating the substrate to a temperature between about 550° C. and about 900° C.; f. introducing nitrogen into the ion gun; g. setting the nitrogen gun discharge voltage at a level sufficient to strike a plasma; h. increasing the nitrogen gun filament current until the plasma strikes; i. setting the nitrogen gun anode potential sufficient to extract ions; j. depositing gallium onto the GaN growing surface at flux rate higher than the gallium desorbtion rate from the GaN growing surface.
Claim 16
Independent Claim
142 words
The method of making p-type GaN comprising, a. mounting a substrate on a heater; b. placing the heater and substrate in a vacuum chamber; c. biasing the substrate at a voltage sufficient to decelerate ions that approach its GaN growing surface; d. evacuating the chamber to a pressure low enough to operate an ion gun, mounted on or within the chamber; e. heating the substrate to a temperature between about 550° C. and about 900° C.; f. introducing nitrogen into the ion gun; g. setting the nitrogen gun discharge voltage at a level sufficient to strike a plasma; h. increasing the nitrogen gun filament current until the plasma strikes; i. setting the nitrogen gun anode potential sufficient to extract ions; j. depositing gallium onto the GaN growing surface at flux rate higher than the gallium desorbtion rate from the GaN growing surface.
Claim 17
Dependent Claim
17 words
The method of claim 12 wherein, the substrate is cleaned before it is mounted on the heater.
Claim 18
Dependent Claim
18 words
The method of claim 12 wherein components in the vacuum chamber are outgassed before GaN growth is started.
Claim 19
Dependent Claim
29 words
The method of claim 12 wherein, a buffer layer of GaN is grown at a temperature between about 490° C. and about 550° C. before increasing the growing temperature.
Claim 20
Dependent Claim
15 words
The method of claim 12 wherein the buffer layer is grown for about 5 minutes.
Claim 21
Dependent Claim
21 words
The method of claim 12 wherein the substrate is biased at a voltage between about 5 volts and about 25 volts.
Claim 22
Dependent Claim
21 words
The method of claim 17 wherein the substrate is biased at a voltage between about 12 volts and about 22 volts.
Claim 23
Dependent Claim
21 words
The method of claim 18 wherein the substrate is biased at a voltage between about 16 volts and about 20 volts.
Claim 24
Dependent Claim
14 words
The method of claim 19 wherein the substrate is biased at about 18 volts.
Claim 25
Dependent Claim
27 words
The method of claim 12 wherein the substrate voltage is biased at a voltage between about 7 volts and about 17 volts lower than the anode voltage.
Claim 26
Dependent Claim
22 words
The method of claim 21 wherein the substrate voltage is biased at a voltage about 12 volts lower than the anode voltage.
Claim 27
Dependent Claim
20 words
The method of claim 12 wherein the pGaN is grown at temperatures between about 550° C. and about 700° C.
Claim 28
Dependent Claim
20 words
The method of claim 23 wherein the pGaN is grown at temperatures between about 590° C. and about 610° C.
Claim 29
Dependent Claim
14 words
The method of claim 24 wherein the pGaN is grown at about 600° C.
Claim 30
Dependent Claim
21 words
The method of claim 12 wherein the nitrogen ion gun is a 3 cm single grid Model II Kauffman ion gun.
Claim 31
Dependent Claim
20 words
The method of claim 26 wherein the gun's discharge voltage is set between about 25 volts and about 40 volts.
Claim 32
Dependent Claim
15 words
The method of claim 27 wherein the discharge voltage is set at about 25 volts.
Claim 33
Dependent Claim
20 words
The method of claim 26 wherein the gun's filament current is set between about 6 Amps and about 8 Amps.
Claim 34
Dependent Claim
20 words
The method of claim 26 wherein the gun's anode voltage is set between about 27 volts and about 40 volts.
Claim 35
Dependent Claim
15 words
The method of claim 30 wherein the anode voltage is set at about 30 volts.
Claim 36
Dependent Claim
24 words
The method of claim 12 wherein the anode voltage is set between about 2 volts and about 6 volts higher than the discharge voltage.
Claim 37
Dependent Claim
19 words
The method of claim 32 wherein the anode voltage is set about 3 volts higher than the discharge voltage.
Claim 38
Dependent Claim
13 words
The method of claim 12 wherein the gallium source is a Knudsen cell.
Claim 39
Dependent Claim
17 words
The method of claim 34 wherein the gallium source is a W-A Technologies Series 3 Knudsen cell.
Claim 40
Dependent Claim
29 words
The method of claim 35 wherein the gallium source is a W-A Technologies Series 3 Knudsen cell set at a temperature between about 1000° C. and about 1250° C.
Claim 41
Dependent Claim
25 words
The method of claim 36 wherein the gallium source is a W-A Technologies Series 3 Knudsen cell set at a temperature at about 1075° C.
Claim 42
Dependent Claim
24 words
The method of claim 12 wherein the gallium flux is between about 10 13 atoms/cm 2 -sec and about 10 15 atoms/cm 2 -sec.
Claim 43
Dependent Claim
24 words
The method of claim 38 wherein the gallium flux is between about 10 14 atoms/cm 2 -sec and about 10 15 atoms/cm 2 -sec.
Claim 44
Dependent Claim
17 words
The method of claim 12 wherein the gallium flux is about ten times the nitrogen ion flux.
Claim 45
Dependent Claim
33 words
The method of claim 12 additionally comprising depositing magnesium on the GaN growing surface at a rate between about 10 3 to about 10 7 times less than the deposition rate of gallium.
Claim 46
Dependent Claim
19 words
The method of claim 41 wherein the substrate bias is set to between about 0 to about 5 volts.
Claim 47
Dependent Claim
20 words
The method of claim 41 wherein the substrate bias is set to between about 5 volts to about 38 volts.
Claim 48
Dependent Claim
20 words
The method of claim 43 wherein the substrate bias is set to between about 15 volts to about 21 volts.
Claim 49
Dependent Claim
59 words
The method of claim 12 additionally comprising, a. cooling GaN; b. placing GaN in a sealable container; c. placing small pieces of Mg in the container; d. introducing nitrogen into the container; e. sealing the container; heating the sealed container to temperatures between about 770° C. and about 820° C. for times longer than at least about 50 hours.
Claim 50
Dependent Claim
19 words
The method of claim 45 wherein the sealed container is heated to about 800° C. for about 80 hours.
Claim 51
Dependent Claim
19 words
The method of claim 45 wherein the substrate bias is set to between about 0 to about 5 volts.
Claim 52
Dependent Claim
20 words
The method of claim 45 wherein the substrate bias is set to between about 5 volts to about 38 volts.
Claim 53
Dependent Claim
20 words
The method of claim 48 wherein the substrate bias is set to between about 15 volts to about 21 volts.
Claim 54
Dependent Claim
55 words
The method of claim 12 additionally comprising, a. implanting magnesium ions having an energy of between about 5 and 79 keV into the GaN surface; b. annealing the implanted GaN compound in flowing nitrogen at temperatures between about 700° C. and about 900° C. for times of between about 15 minutes to about 90 minutes.
Claim 55
Dependent Claim
22 words
The method of claim 50 wherein the implantation energy of the Mg ions is between about 20 keV and about 70 keV.
Claim 56
Dependent Claim
22 words
The method of claim 51 wherein the implantation energy of the Mg ions is between about 40 keV and about 60 keV.
Claim 57
Dependent Claim
64 words
A light emitting diode comprising, a. an n-GaN layer; b. a p-GaN layer comprising III-V semiconductor wherein i) the ratio of III semiconductor to nitrogen is between about 1.0:0.95 and stoichiometric ii) the V semiconductor comprises nitrogen; iii) the III semiconductor comprises at least 80% gallium; and iv) charge carriers are primarily holes, overlying the n-GaN layer; and electrical contacts attached to each layer.
Claim 58
Dependent Claim
64 words
A light emitting diode comprising, a. an n-GaN layer; b. a p-GaN layer comprising III-V semiconductor wherein i) the ratio of III semiconductor to nitrogen is between about 1.0:0.95 and stoichiometric ii) the V semiconductor comprises nitrogen; iii) the III semiconductor comprises at least 80% gallium; and iv) charge carriers are primarily holes, overlying the n-GaN layer; and electrical contacts attached to each layer.
Claim 59
Dependent Claim
68 words
A light emitting diode comprising, a p-GaN layer comprising III-V semiconductor wherein i) the ratio of III semiconductor to nitrogen is between about 1.0:0.95 and stoichiometric ii) the V semiconductor comprises nitrogen; iii) the III semiconductor comprises at least 80% gallium; and iv) charge carriers are primarily holes, overlying the n-GaN layer; b. an n-GaN layer overlying the p-GaN layer; and c. electrical contacts attached to each layer.
Claim 60
Dependent Claim
68 words
A light emitting diode comprising, a p-GaN layer comprising III-V semiconductor wherein i) the ratio of III semiconductor to nitrogen is between about 1.0:0.95 and stoichiometric ii) the V semiconductor comprises nitrogen; iii) the III semiconductor comprises at least 80% gallium; and iv) charge carriers are primarily holes, overlying the n-GaN layer; b. an n-GaN layer overlying the p-GaN layer; and c. electrical contacts attached to each layer.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2000-08-11 | 2001-02-10 | 2001-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-11 | 2005-02-10 | 2005-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-11 | 2009-02-10 | 2009-08-12 | $7700.00 | Window Closed / Lapsed |