| 摘要 |
PURPOSE:To obtain the thyristor of high strength against turn-off breakdown by a method wherein a semiconductor substrate having an impurity layer which is a part of the first conductivity type base layer and a semiconductor substrate having an impurity layer which is the remaining of this base layer are adhered to each other by heat treatment, and this adhered substrate is used to form a pnpn wafer. CONSTITUTION:A material into which a p-type layer 12, part of a p-base layer, is formed on the surface of an n<-> type Si substrate 11 serving as a high-resistant n-base layer and a p-type Si substrate, the remaining of the low-resistant p-base layer, are prepared. Substrate surfaces to be adhered to each other are polished into mirror. The substrates 11, 13 after washing and drying are brought into contact with each other under a clean atmosphere and heat-treated at 200 deg.C or more, thus obtaining an adhered substrate enhanced in adhesion strength. This adhered substrate is polished on the p-type substrate 13 side, and an n- emitter layer 15 is formed by diffusing phosphorus or another impurity; besides, a p-emitter layer 16 is formed on the back of the n<-> type Si substrate 11. Thereafter, the n-emitter layer is divided into a plurality; electrodes 17-19, a protection film 20, etc. are formed, and GTO is completed.
|
