US3773571A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of semiconductor ternary compounds of controlled composition by predetermined cooling rates
Assignee: International Business Machines Corp
•
Filing: 1967-06-15
•
Granted: 1973-11-20
•
Expires: 1987-06-15
Abstract
Abstract Semiconductor ternary compounds are prepared by liquid phase epitaxy by using control of the cooling rate to control the crystalline composition. In particular, Ga1 xAlxAs is grown on a GaAs substrate and has a homogeneous composition. This is accomplished by cooling a melt of Ga and Al saturated with GaAs in Al2O3 crucible using a single crystalline wafer of GaAs as the substrate. Critical parameters are an excess of GaAs, the Al/Ga ratio, the growth temperature, and the cooling rate. Electroluminescent diodes made from the Ga1 xAlxAs have relatively high quantum efficiencies, e.g., 3.3 percent when emitting light of energy 1.70 electron volts through an epoxy dome with a matching index of refraction. Illustratively, for the electroluminescent diodes with 3.3 percent quantum efficiency, exemplary parameters included a melt composition of 20 grams of Ga, 50 milligrams of Al, growth rate of 1*C per minute over a temperature range of 950*C to 920*C for n-type dopant of 5 milligrams of Te and an additional 50 milligrams of Zn from 920*C to 860*C for counter doping to ptype. Further, a GaAs - Ga1 xAlxAs heterojunction is obtained if the cooling rate is changed abruptly from 1*C per minute to greater than 10*C per minute.
Inventors
- 👤 H Rupprecht
- 👤 J Woodall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 00:45
CPC Classifications
C; C30; C30B; C30B29/00; C30B29/10; C30B29/40; C30B19/00; C30B19/02; C30B19/04; C30B19/06; C30B19/062; H; H10; H10H; H10H20/00; H10H20/01; H10H20/011; H10H20/013; H10P; H10P14/00; H10P14/20; H10P14/26; H10P14/263; H10P14/265; H10P14/29; H10P14/2901; H10P14/2907; H10P14/2911; H10P14/34; H10P14/3402; H10P14/3414; H10P14/3418; H10P14/3421; H10P14/3438; H10P14/3441; H10P14/3442; H10P14/3444; H10P14/3446; H10P95/00; Y; Y10; Y10S; Y10S148/00; Y10S148/065; Y10S438/00; Y10S438/936
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
142 words
Method for preparing a given composition of a single crystalline semiconductor multicomponent ternary compound structure with more than two components and with a continuous range of compositions by liquid phase epitaxy comprising the steps of: providing an equilibrium liquid solution at a given temperature comprised of the components of a semiconductor multicomponent compound with more than two components and with a continuous range of compositions; providing a crystalline solid substrate in said liquid in equilibrium with said liquid at said given temperature and having a lattice constant compatible with the lattice constant of said crystalline compound; and cooling the system of said liquid and said solid at a given programmed and variable rate to induce liquid phase epitaxial growth of said crystalline semiconductor multicomponent compound with more than two components on said crystalline substrate whose composition is determined by said cooling rate.
Claim 2
Dependent Claim
98 words
Method of forming a layer of graded composition comprising the steps of: providing an equilibrium liquid solution at a given temperature of the components of a semiconductor ternary compound with a continuous range of compositions; providing a solid single crystalline substrate having a lattice constant which is compatible with the lattice constant of said ternary compound in equilibrium with said liquid at said given temperature; and cooling the system of said liquid and said solid at a variable rate to grow by liquid phase epitaxy a layer of said semiconductor ternary compound of graded composition on said substrate.
Claim 3
Dependent Claim
16 words
Method as set forth in claim 3 wherein said ternary compound is a III-V semiconductor compound.
Claim 4
Dependent Claim
31 words
Method according to claim 3 wherein said variable cooling rate consists of one cooling rate followed by another different cooling rate to form a heterojunction in said semiconductor ternary compound layer.
Claim 5
Dependent Claim
32 words
Method according to claim 5 wherein said components of said ternary compound are Ga, Al and As and said heterojunction consists of a layer of Ga1 xAlxAs adjacent a layer of GaAs.
Claim 6
Dependent Claim
48 words
Method according to claim 6 wherein said one cooling rate is selected to be from 0.5*C to 0.1*C per minute for forming said layer of Ga1 xAlxAs and said another different cooling rate is selected to be greater than 10*C per minute for forming said layer of GaAs.
Claim 7
Dependent Claim
163 words
Method for preparing a given composition of a structure comprising a crystalline semiconductor multicomponent compound with more than two components and with a continuous range of compositions by liquid phase epitaxy comprising the steps of: providing an equilibrium liquid solution at a given temperature comprised of the components of a semiconductor multicomponent compound with more than two components and with a continuous range of compositions; providing a crystalline solid substrate in said liquid in equilibrium with said liquid at said given temperature and having a lattice constant compatible with the lattice constant of said crystalline compound; and producing a given composition of said compound within said continuous range of compositions by cooling the system of said liquid and said solid at a given programmed and predetermined and fixed rate to induce liquid phase epitaxial growth of said crystalline semiconductor multicomponent compound with more than two componenTs on said crystalline substrate whose structural composition is said given composition as predetermined by said cooling rate.
Claim 8
Dependent Claim
14 words
Method according to claim 8 wherein said crystalline semiconductor compound is a ternary compound.
Claim 9
Dependent Claim
83 words
Method according to claim 9 wherein: said ternary compound is Ga1 xAlx As; said substrate is Ga As; said liquid solution contains Ga, Al, As and excess GaAs solid with the Al/Ga weight ratio being in the range of approximately 2 X 103 to 8 X 103; said substrate is at temperature during growth of said Ga1 xAlx As compound in the range of approximately 1,000*C to 860*C; and said cooling rate is in the range of approximately 0.1*C to 10*C per minute.
Claim 10
Dependent Claim
16 words
Method as set forth in claim 9 wherein said ternary compound is a III-V semiconductor compound.
Claim 11
Dependent Claim
13 words
Method according to claim 9 wherein said ternary compound is single crystalline structure.
Claim 12
Dependent Claim
26 words
Method according to claim 12 wherein said single crystalline structure is Ga1 xAlxAs, and said Al/Ga weight ratio in said liquid solution is less than 0.5.
Claim 13
Dependent Claim
24 words
Method according to claim 13 wherein said programmed and predetermined and fixed cooling rate is selected to be from 0.5*C to 1*C per minute.
Claim 14
Dependent Claim
218 words
Method of forming a p-n junction in a single crystalline structure of a semiconductor ternary compound with a continuous range of compositions comprising the steps of: providing an equilibrium liquid solution at a given temperature comprised of the components of a ternary compound with a continuous range of compositions; providing a single crystalline solid substrate in said liquid in equilibrium with said liquid at said temperature and having a lattice constant compatible with the lattice constant of said single crystalline structure; adding uniformly a first semiconductor dopant to said liquid of one conductivity type; producing a first layer of said compound having a first given composition within said continuous range of compositions by cooling the system of said liquid and said solid at a given predetermined and fixed rate to grow by liquid phase epitaxy said layer of said first conductivity type on said substrate; adding uniformly to said doped liquid a second semiconductor counter dopant of opposite conductivity type to said first dopant; and producing a second layer of said compound having a second given composition within said continuous range of compositions by cooling said counter doped system of said liquid and said solid at said given rate to established by liquid phase epitaxy a p-n junction in a single crystalline semiconductor structure of said ternary compound.
Claim 15
Dependent Claim
16 words
Method as set forth in claim 15 wherein said ternary compound is a III-V semiconductor compound.
Claim 16
Dependent Claim
11 words
Method according to claim 15 wherein said p-n junction is electroluminescent.
Claim 17
Dependent Claim
45 words
Method according to claim 17 wherein said single crystalline ternary compound is Ga1 xAlxAs and said first dopant is Te for n-type conductivity and said second dopant is Zn for p-type conductivity, and said Al/Ga weight ratio in said liquid solution is less than 0.5.
Claim 18
Dependent Claim
22 words
Method according to claim 18 wherein said predetermined and fixed cooling rate is selected to be from 0.5*C to 1*C per minute.
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) | 1976-11-19 | 1977-05-21 | 1977-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-19 | 1981-05-21 | 1981-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-19 | 1985-05-21 | 1985-11-20 | $7700.00 | Window Closed / Lapsed |