Atomic layer epitaxy of compound semiconductor

• US 5,270,247 A
• Filed: 07/08/1992
• Issued: 12/14/1993
• Est. Priority Date: 07/12/1991
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Ohtuka, Nobuyuki, Kodama, Kunihiko, Ozeki, Masashi, Sakuma, Yoshiki
• Primary Examiner(s): Hearn, Brian E.
• Assistant Examiner(s): Picardat, Kevin M.
• Application Number:
  US07/910,766
• Time in Patent Office: 524 Days
• Field of Search: 437/133, 437/107, 437/108, 437/110, 437/81, 148/DIG. 25, 148/DIG. 41, 148/DIG. 48, 148/DIG. 57, 148/DIG. 72, 156/610, 156/613
• US Class Current: 117/89
• CPC Class Codes: H01L 21/02392 Phosphides
• CPC Class Codes: H01L 21/02395 Arsenides
• CPC Class Codes: H01L 21/02507 Alternating layers, e.g. superlattice
• CPC Class Codes: H01L 21/02543 Phosphides
• CPC Class Codes: H01L 21/02546 Arsenides
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: Y10S 148/048 Energy beam assisted EPI growth
• CPC Class Codes: Y10S 148/072 Heterojunctions

Abstract

A heterojunction between In-containing compound semiconductors in which the interface thereof is controlled at an atom level is provided by a process of atomic layer epitaxy (ALE) in which hydrogen gas is utilized as a carrier gas and as a purge gas for a separation of source gases. The time for which the purge gas is supplied can be utilized for controlling the ALE.

Claims

1. A process for growing a crystalline compound semiconductor, comprising the steps of:

heating a crystalline substrate to a predetermined temperature in a vacuum chamber, and

at said predetermined temperature of the crystalline substrate and in the following sequence;

supplying a first source gas for a III-group element containing an organic In compound diluted with hydrogen over said crystalline substrate under a predetermined pressure,

discharging the first source gas,

supplying a second source gas for a first V-group element over said crystalline substrate under a predetermined pressure,

discharging the second source gas,

supplying a third source gas for a III-group element containing an organic In compound diluted with hydrogen over said crystalline substrate under a predetermined pressure,

discharging the third source gas,

supplying a fourth source for a second V-group element over said crystalline substrate under a predetermined pressure, and

discharging the forth source gas,

wherein said first and second V-group elements have at least different compositions or different constituent elements.

2. A process according to claim 1, wherein said steps of supplying said first and second source gases are repeated to grow a first In-containing compound semiconductor layer on said crystalline substrate, before said steps of supplying said third and fourth source gases are repeated to grow a second In-containing compound semiconductor layer on said first In-containing compound semiconductor layer.

3. A process according to claim 1, wherein said predetermined temperature is in a range of 300°

to 450°

C.

4. A process according to claim 1, wherein said second and fourth source gases contain hydrogen gas.

5. A process according to claim 1, wherein said discharge of the first to fourth source gases are carried out by supplying a hydrogen gas over said crystalline substrate under a predetermined pressure to thereby purge away the source gas.

6. A process according to claim 1, wherein each of said predetermined pressures in said steps of supplying said first, second, third and fourth source gases is a certain pressure in a range of 5 torr to 1000 torr.

7. A process according to claim 1, wherein said organic compound of In is trimethyl indium and said second and fourth source gases comprise arsine and phosphine.

8. A process according to claim 2, wherein a heterojunction is one selected from the group consisting of InAs/InP, InAsP/InP and InAs/InAsP.

9. A process according to claim 5, wherein in said purging steps after the steps of supplying said second and fourth source gases to adsorp the first and second V-group elements on the underlying crystalline substrate, the hydrogen gas is supplied in a short time such that the adsorped V-group element is not desorped.

10. A process according to claim 9, wherein said second and fourth source gases comprise arsin and said short time satisfies the following formula:

space="preserve" listing-type="equation">log t≦

-(7.09/4.75)T+7.33

where T stands for a temperature of the crystalline substrate in °

C. and t stands for the time of supplying the hydrogen gas, in seconds.

11. A process for growing a crystalline compound semiconductor, comprising the steps of:

supplying a III-group element source gas over a crystalline substrate,

supplying a hydrogen gas over the crystalline substrate to purge away the III-group element source gas for a time,

supplying a V-group element source gas over the crystalline substrate, and

supplying a hydrogen gas over the crystalline substrate to purge away the V-group element source gas for a time, and

repeating said steps to grow a III-V compound semiconductor layer on the crystalline substrate,

wherein said time of supplying the hydrogen gas for said purge is controlled to thereby control a growth rate of said compound semiconductor.

12. A process for growing a crystalline compound semiconductor, comprising the steps of:

supplying a III-group element source gas over a crystalline substrate,

supplying a hydrogen gas over the crystalline substrate to purge away the III-group element source gas,

supplying a V-group element source gas over the crystalline substrate,

supplying a hydrogen gas over the crystalline substrate to purge away the V-group source gas, and

supplying a dopant source over the crystalline substrate, and

repeating the above steps to grow a doped III-V compound semiconductor layer on the crystalline substrate for a time,

wherein said time of supplying the hydrogen gas is controlled to thus control a concentration of said dopant in said doped-III-V compound semiconductor layer.