Vapor phase epitaxy method

Patent metadata

Field	Value
Publication number	US-12444604-B2
Application number	US-202017129732-A
Country	US
Kind code	B2
Filing date	Dec 21, 2020
Priority date	Dec 20, 2019
Publication date	Oct 14, 2025
Grant date	Oct 14, 2025

Abstract

A vapor phase epitaxy method of growing a III-V layer with a doping profile that changes from n-doping to p-doping on a surface of a substrate or a preceding layer in a reaction chamber from the vapor phase of an epitaxial gas flow, comprising at least one carrier gas, a first precursor for a first element from main group III and at least one second precursor for a first element from main group V, and fed into the reaction chamber, wherein, when a first growth level is reached, an initial n-doping level is set by means of a ratio, leading to a p-doping, of a first mass flow of the first precursor to a second mass flow of the second precursor in the epitaxial gas flow and with the addition of a third mass flow of a third precursor for an n-type dopant to the epitaxial gas flow, subsequently.

First claim

What is claimed is:

1. A vapor phase epitaxy method comprising:
growing a Ill-V layer with a doping profile that changes from n-doping to p-doping on a surface of a substrate or a preceding layer in a reaction chamber from a vapor phase from an epitaxial gas flow comprising a carrier gas, at least one first precursor for an element from main group III, and at least one second precursor for an element from main group V;
setting, when a first growth height is reached, an initial n-doping level in the epitaxial gas flow via a ratio, leading to a p-doping, of a first mass flow of the first precursor to a second mass flow of the second precursor and with an addition of a third mass flow of a third precursor for an n-type dopant to the epitaxial gas flow; and
changing the third mass flow and/or the ratio between the first and second mass flow stepwise or continuously over a junction region layer with a growth height of at least 10 μm until a target p-doping level is reached.

2. The vapor phase epitaxy method according to claim 1 , wherein the initial n-doping level is at most 1·10 16 cm −3 .

3. The vapor phase epitaxy method according to claim 1 , wherein the target p-doping level is at most 5·10 15 cm −3 .

4. The vapor phase epitaxy method according to claim 1 , wherein, after the target p-doping level has been reached, growth is continued further over a growth height of at least 10 μm with the settings for the target p-doping level.

5. The vapor phase epitaxy method according to claim 1 ,
wherein after the target p-doping level has been reached, a second target p-doping level is set by changing the third mass flow and/or by changing the ratio between the first and second mass flow, and
wherein the second target p-doping level is greater than the target p-doping level.

6. The vapor phase epitaxy method according to claim 1 , wherein the growth height of the junction region layer is at least 30 μm.

7. The vapor phase epitaxy method according to claim 1 , wherein the doping over the junction region layer is changed in steps of at most 1·10 13 cm −3 over 5 μm.

8. The vapor phase epitaxy method according to claim 1 , wherein the doping over the junction region layer is changed in at least four steps.

9. The vapor phase epitaxy method according to claim 1 , wherein, after the initial n-doping level has been reached and before the junction region layer has grown, the initial n-doping level is abruptly reduced to a second initial n-doping level or set abruptly to an initial p-doping level of at most 1·10 15 cm −3 by reducing the third mass flow in the epitaxial gas flow.

10. The vapor phase epitaxy method according to claim 1 , wherein the third precursor is monosilane.

11. The vapor phase epitaxy method according to claim 1 , wherein the element of main group Ill is gallium and the element of main group V is arsenic.

12. The vapor phase epitaxy method according to claim 1 ,
wherein, after the target p-doping level has been reached over a growth height, a second target p-doping level is set by abruptly changing the third mass flow and/or by abruptly changing the ratio of the first mass flow to the second mass flow, and
wherein the second target p-doping level is greater than a target n-doping level.

13. The vapor phase epitaxy method according to claim 1 , wherein the initial n-doping level is at most 1·10 15 cm −3 .

14. The vapor phase epitaxy method according to claim 1 , wherein the initial n-doping level is at most 5·10 14 cm −3 .

15. The vapor phase epitaxy method according to claim 1 , wherein the target p-doping level is at most 1·10 15 cm −3 .

16. The vapor phase epitaxy method according to claim 1 , wherein the growth height of the junction region layer is at least 60 μm.

17. The vapor phase epitaxy method according to claim 1 , wherein, after the initial n-doping level has been reached and before the junction region layer has grown, the initial n-doping level is abruptly reduced to a second initial n-doping level or set abruptly to an initial p-doping level of at most 5·10 14 cm −3 by reducing the third mass flow in the epitaxial gas flow.

Assignees

• Azur Space Solar Power Gmbh

Inventors

• WAECHTER Clemens
• Keller Gregor
• Wierzkowski Thorsten
• Fuhrmann Daniel

Classifications

• H10P14/3444

  P-type · CPC title

• H10P14/3421

  Arsenides · CPC title

• H10P14/24

  using chemical vapour deposition [CVD] · CPC title

• H10P14/3442 Primary

  N-type · CPC title

• H10D62/10

  Shapes, relative sizes or dispositions of the regions of the semiconductor bodies; Shapes of the semiconductor bodies · CPC title