US5387545A
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US
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Impurity diffusion method
Assignee: Renesas Electronics Corp
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Filing: 1991-12-12
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Granted: 1995-02-07
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Expires: 2011-12-12
Abstract
Abstract An impurity diffusion method which can control a surface atomic concentration from a low to a high surface atomic concentration with a good uniformity is provided. Natural oxide is removed from the surface of a semiconductor substrate with a deoxidizing atmosphere gas as a diffusion atmosphere gas in advance, and then an impurity gas is passed thereto, while passing the deoxidizing atmosphere gas thereto, thereby conducting the diffusion. Flow rate or concentration of impurity of the impurity gas is so set that the impurity atomic concentration of the diffusion layer can be controlled by the flow rate or the concentration of impurity of the impurity gas. The impurity atomic concentration of the diffusion layer can be controlled by adjusting the flow rate or concentration of impurity of the impurity gas, and a diffusion layer having a low impurity atomic concentration can be formed. A shallow junction having a depth of not more than 50 nm can be formed.
Inventors
- 👤 Yukihiro Kiyota
- 👤 Tohru Nakamura
- 👤 Takahiro Onai
- 👤 Taroh Inada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:46
CPC Classifications
H; H10; H10D; H10D10/00; H10D10/01; H10D10/051; H10P; H10P32/00; C; C30; C30B; C30B31/00; C30B31/06; H10P32/10; H10P32/14; H10P32/1408; H10P32/17; H10P32/171; Y; Y10; Y10S; Y10S148/00; Y10S148/017
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
123 words
An impurity diffusion method for forming a diffusion layer by diffusing an impurity of a first conductivity type into a semiconductor material, which comprises removing natural oxides from the surface of the semiconductor material with an atmosphere gas containing a deoxidizing gas, then passing an impurity gas comprising a compound containing the impurity and hydrogen to the surface of the semiconductor material while passing the atmosphere gas thereto, thereby diffusing the impurity into the surface of the semiconductor material directly from a gas phase where a flow rate or concentration of impurity of the impurity gas is set, so that the impurity atomic concentration of the diffusion layer is controlled by the flow rate or the concentration of impurity of the impurity gas.
Claim 2
Dependent Claim
123 words
An impurity diffusion method for forming a diffusion layer by diffusing an impurity of a first conductivity type into a semiconductor material, which comprises removing natural oxides from the surface of the semiconductor material with an atmosphere gas containing a deoxidizing gas, then passing an impurity gas comprising a compound containing the impurity and hydrogen to the surface of the semiconductor material while passing the atmosphere gas thereto, thereby diffusing the impurity into the surface of the semiconductor material directly from a gas phase where a flow rate or concentration of impurity of the impurity gas is set, so that the impurity atomic concentration of the diffusion layer is controlled by the flow rate or the concentration of impurity of the impurity gas.
Claim 3
Dependent Claim
28 words
An impurity diffusion method according to claim 1, wherein the deoxidizing gas is a gas having a function to convert S i O 2 to S i O.
Claim 4
Dependent Claim
15 words
An impurity diffusion method according to claim 1, wherein the deoxidizing gas is hydrogen gas.
Claim 5
Dependent Claim
30 words
An impurity diffusion method according to claim 1, wherein the surface atomic concentration of the diffusion layer is lower than the solid solubility of the impurity into the semiconductor material.
Claim 6
Dependent Claim
30 words
An impurity diffusion method according to claim 1, wherein the impurity is made to diffuse by heating after the natural oxide is removed from the surface of the semiconductor material.
Claim 7
Dependent Claim
35 words
An impurity diffusion method according to claim 1, wherein diffusion of the impurity and activation of the diffused impurity are carried out simultaneously, while passing the impurity gas to the surface of the semiconductor material.
Claim 8
Dependent Claim
43 words
An impurity diffusion method according to claim 1, wherein the impurity is directly diffused from the gas phase onto the surface of the semiconductor material without forming a shallow diffusion layer of the impurity on the surface of the semiconductor material in advance.
Claim 9
Dependent Claim
26 words
An impurity diffusion method according to claim 1, wherein the impurity diffusion is directed to formation of base region or emitter region of a bipolar transistor.
Claim 10
Dependent Claim
21 words
An impurity diffusion method according to claim 1, wherein the impurity gas is B 2 H 6 or PH 3 .
Claim 11
Dependent Claim
28 words
An impurity diffusion method according to claim 1, wherein a flow rate ratio of the impurity gas to the deoxidizing gas is not more than 1×10 -4 .
Claim 12
Dependent Claim
18 words
An impurity diffusion method according to claim 1, wherein said semiconductor material is a semiconductor single crystal substrate.
Claim 13
Dependent Claim
21 words
An impurity diffusion method according to claim 1, wherein said semiconductor material is a silicon layer formed on a semiconductor substrate.
Claim 14
Dependent Claim
21 words
An impurity diffusion method according to claim 1, wherein said semiconductor material is an epitaxial layer formed on a semiconductor substrate.
Claim 15
Dependent Claim
29 words
An impurity diffusion method according to claim 1, wherein the impurity gas is a gas comprising a compound of a Group III or Group V impurity element and hydrogen.
Claim 16
Dependent Claim
32 words
An impurity diffusion method according to claim 1, wherein the impurity gas comprises a compound containing an impurity element selected from the group consisting of boron, phosphorus, arsenic and antimony and hydrogen.
Claim 17
Dependent Claim
36 words
An impurity diffusion method according to claim 1, wherein the impurity gas comprises a compound selected from the group consisting of B 2 H 6 , PH 3 , AsH 3 , and SbH 3 .
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