US3602778A
Expired / Lapsed
US
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Zener diode and method of making the same
Assignee: Hitachi Ltd
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Filing: 1968-09-24
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Granted: 1971-08-31
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Expires: 1988-09-24
Abstract
Abstract A Zener diode having a low dynamic impedance and a low leakage current which comprises a first layer of a single crystalline semiconductor of silicon doped with a P-type or N-type impurity and a second layer formed by gas-phase epitaxial growth of silicon and doped with an impurity of the opposite type. In the Zener diode, the impurity concentrations of the first and second layers are 1 X 1017 to 4 X 1019 atoms/cm.3 and 1 X 1019 to 1 X 1021 atoms/cm.3, respectively, and there is an impurity concentration gradient of from 2 X 1021 to 7 X 1023 atoms/cm.4 across the PN junction.
Inventors
- 👤 Mitsuru Ura
- 👤 Takuzo Ogawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:29
CPC Classifications
H; H10; H10P; H10P32/00; H10D; H10D99/00; H10P14/00; H10P14/20; H10P14/24; H10P14/29; H10P14/2901; H10P14/2902; H10P14/2905; H10P14/34; H10P14/3402; H10P14/3404; H10P14/3411; H10P14/3438; H10P14/3441; H10P14/3442; H10P14/3444; Y; Y10; Y10S; Y10S438/00; Y10S438/936; Y10S438/983
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
46 words
A Zener diode according to claim 1, wherein said second layer is a high-doped region which has such a thickness that the PN junction is prevented from being physically as well as electrically affected by a conductor electrode which is deposited later on said second layer.
Claim 2
Dependent Claim
40 words
A Zener diode according to claim 2, wherein said second layer contacts with its flat and smooth surface with said first layer which is a low-doped region, and said second layer has a thickness of from 5 to 35 microns.
Claim 3
Dependent Claim
21 words
A Zener diode according to claim 1, wherein said first layer is formed by means of gas-phase epitaxial growth of silicon.
Claim 4
Dependent Claim
50 words
A Zener diode according to claim 4, wherein the impurity concentration gradient at and in the vicinity of the PN junction formed by said first and second layers is approximately in the range of from z X 1021 to 7 X 1023 atoms/cm.4 and the region including said PN junction.
Claim 5
Dependent Claim
30 words
A Zener diode according to claim 4, wherein a low resistance layer is further provided on the side of said first layer where said metal conductor is to be provided.
Claim 6
Dependent Claim
19 words
A Zener diode according to claim 1, wherein said second layer has a thickness of 10 to 35 microns.
Claim 7
Dependent Claim
19 words
A Zener diode according to claim 1, wherein said second layer has a thickness of 20 to 30 microns.
Claim 8
Dependent Claim
107 words
A Zener diode comprising a silicon body including a low-doped region containing a P-type impurity in an impurity concentration of from 1 X 1017 to 4 X 1019 atoms/cm.3, and a high-doped region containing an N-type impurity in an impurity concentration of from 1 X 1019 to 1 X 1021 atoms/cm.3, wherein at least said high-doped region is formed by means of gas-phase epitaxial growth of silicon, the PN junction formed at the interface of said two regions has an impurity concentration gradient of from 2 X 1021 to 7 X 1023 atoms/cm.4, and a metal conductor is electrically connected to each of the said two regions.
Claim 9
Dependent Claim
24 words
A Zener diode according to claim 9, wherein said metal conductor is a film of aluminum alloyed to said regions for ohmic contact therewith.
Claim 10
Dependent Claim
19 words
A Zener diode according to claim 9, wherein the metal conductors consist of nickel-gold provided by means of plating.
Claim 11
Dependent Claim
50 words
A Zener diode according to claim 9, wherein said low-doped region is formed by means of gas-phase epitaxial growth of silicon, and the relation between its impurity concentration N and Zener breakdown voltage VZ is given by log VZ (-0.09 x2+0.29 x+1.06) 1 where x log (N/ 2 X 1018).
Claim 12
Dependent Claim
50 words
A Zener diode according to claim 9, wherein said low-doped region is formed by means of gas-phase epitaxial growth of silicon, and the relation between its impurity concentration N and Zener breakdown voltage is given by log VZ (0.075 x X 2+0.38 x+1.36 1 where x log (N/2 X 1018).
Claim 13
Independent Claim
166 words
A method of making Zener diodes comprising the steps of: smoothing and cleaning a surface of a single crystalline silicon wafer having a predetermined conductivity type and an impurity concentration of from 1 X 1017 to 4 X 1019 atoms/cm.3, positioning said wafer within an epitaxial growth reactor provided with heating means and having been cleaned with a carrier gas, introducing into said reactor a starting material and a dopant material for giving a conductivity type opposite to that of said wafer together with a carrier gas, and effecting heat treatment in said reactor at a temperature higher than the decomposition temperature of said starting material so as to precipitate single crystals of silicon at a growth rate of from 3 to 7 microns/min. on said wafer due to decomposition, whereby between said wafer and the layer of said precipitated silicon there is formed a PN junction having an impurity concentration gradient approximately in the range of from 2 X 1021 to 7 X 1023 atoms/mc.4.
Claim 14
Dependent Claim
16 words
A method of making Zener diodes according to claim 14, wherein said starting material is SiH4.
Claim 15
Dependent Claim
24 words
A method of making Zener diodes according to claim 14, wherein said starting material is selected from the group consisting of SiHC13 and SiC14.
Claim 16
Dependent Claim
25 words
A method of making Zener diodes according to claim 15, wherein said heat treatment is effected at a temperature of from 850* to 1100* C.
Claim 17
Dependent Claim
24 words
A method of making Zener diodes according to claim 16, wherein said heat treatment is effected at 1050*temperature of from 10* to 1350* C.
Claim 18
Dependent Claim
32 words
A method of making Zener diodes according to claim 14, wherein the mole ratio of said starting material to said carrier gas is approximately in the range of from 0.02 to 0.05.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-30 | 1975-03-01 | 1975-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-30 | 1979-03-01 | 1979-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-30 | 1983-03-01 | 1983-08-31 | $7700.00 | Window Closed / Lapsed |