| 摘要 |
PURPOSE:To enable a large current to be turned off at a high speed without adversely affecting the voltage prohibiting capability and the ON voltage characteristics by forming a second diffusion layer for suppressing the carrier injection from a first substrate into a second substrate in the region having no first diffusion layer by impurity diffusion. CONSTITUTION:A planished, high-concentration first semiconductor substrate 1 of a first conductivity type and a planished second semiconductor substrate 2 of a second conductivity type are directly bonded and heat-treated thereby to form a wafer. At that time, a first diffusion layer 3 of the first conductivity type is preformed selectively in the surface of the second substrate 2 to be contacted with the first substrate 1, and in the region where the first diffusion layer 3 is not formed, by impurity diffusion from one of the first and second substrates 1, 2 to the other after the substrate bonding, a second diffusion layer 5 is formed which will in effect become a region for suppressing the carrier injection from the first substrate 1 to the second substrate 2. With this, the diffusion layer 5 part virtually functions as an anode-emitter short-circuiting part, whereby a high-speed turn-off characteristic can be obtained. |
