Claims
- 1. A method for manufacturing power thyristors, comprising the steps of:
- preparing an N-type semiconductor substrate;
- forming respective P-type layers on both sides of the semiconductor substrate, one of the layers constituting a P-type base layer, the other layer constituting an anode layer and the N-type substrate located therebetween constituting an N-type base layer;
- forming a first film containing N-type impurities on the P-type base layer and doping the N-type impurities into the surface region of the semiconductor substrate;
- removing the first film;
- heating the semiconductor substrate in order to drive the N-type impurities more deeply into the P-type base layer and making an N-type cathode layer;
- forming an oxide layer on the N-type cathode layer;
- forming respective second films containing phosphorus as gettering material on both the oxide layer and the P-type anode layer in order to increase the carrier lifetime of the P-type base layer;
- removing the second films; and
- diffusing carrier lifetime killer atoms into the N-type base layer in order to decrease the carrier lifetime thereof.
- 2. The method for manufacturing power thyristors according to claim 1, wherein the carrier lifetime killer atoms are gold atoms.
- 3. The method for manufacturing power thyristors according to claim 1, wherein the N-type impurities are phosphorus, arsenic or antimony.
- 4. The method for manufacturing power thyristors according to claim 1, wherein the second films are phosphorsilicate glass films.
- 5. The method for manufacturing power thyristors according to claim 1, wherein the formation of the first film is carried out at a temperature ranging from 700.degree. C. to 1100.degree. C.
- 6. A method for manufacturing power thyristors, comprising the steps of:
- preparing an N-type semiconductor substrate; forming respective P-type layers on both sides of the semiconductor substrate, one of the layers constituting a P-type base layer, the other layer constituting an anode layer and the N-type substrate located therebetween constituting an N-type base layer;
- forming a first film containing N-type impurities on the P-type base layer and doping the N-type impurities into the surface region of the semiconductor substrate;
- removing the first film;
- heating the semiconductor substrate in order to drive the N-type impurities more deeply into the P-type base layer and making an N-type cathode layer;
- forming respective second films containing phosphorus as gettering material on both the oxide layer and the P-type anode layer in order to increase the carrier lifetime of the P-type base layer;
- removing the second films; and
- introducing carrier lifetime killer into the N-type base layer in order to decrease the carrier lifetime thereof.
- 7. The method for manufacturing power thyristors according to claim 6, wherein the carrier lifetime killer is introduced by irradiating the semiconductor substrate by electron radiation.
Priority Claims (2)
Number |
Date |
Country |
Kind |
54-12671 |
Oct 1979 |
JPX |
|
54-154305 |
Nov 1979 |
JPX |
|
Parent Case Info
This application is a continuation-in-part of Application Ser. No. 193,142, filed on Oct. 2, 1980, which previous application is now abandoned.
US Referenced Citations (8)
Non-Patent Literature Citations (2)
Entry |
Azuma et al., "High Power Gate Turn-Off Thyristors", Jpn. J. of Appl. Physics, vol. 17, (1978), Suppl. 17-1, pp. 275-281. |
Azuma et al., "2500 V, 600 A Gate Turn-Off Thyristor (GTO)", International Electron Devices Meeting, Wn., D.C., Dec. 3-5, 1979, pp. 246-249. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
193142 |
Oct 1980 |
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