| 摘要 |
PURPOSE:To relax the concentration of current on turning OFF and improve shut-off resistance by embedding a highly concentrated P-type region at one part of a P-type base layer which is in contact with a cathode/emitter junction surface and selecting breakdown voltage. CONSTITUTION:After diffusing Ga to a single-crystal Si wafer with a metal Ga as a diffusion source, push-in diffusion is performed to form a P-type emitter layer 1 and a P-type base layer 3 in desired Ga diffusion layer. Then, boron diffusion is performed at the central part of a part where an N-type emitter layer 4 is scheduled to be formed on the surface of a P-type base layer 3 for embedding a P-type region 9. This boron diffusion layer has a lower surface concentration as compared with the N-type emitter layer 4 to be formed in the later process and diffusion is deepened. Finally, after etching a gate part, phosphor is selectively diffused to form the N-type emitter layer 4. The N-type emitter layer 4 may be in a shape for covering the entire surface of the cathode part. Then, each electrode 6, 7, and 8 is subjected to ohmic contact for completion. |
