| 摘要 |
PURPOSE:To improve the switching characteristic by forming the base and emitter regions in the semiconductor substrate, which is to be the collector, by a diffusion method, by applying radiation to the entire surface of the substrate in order to increase the switching speed and by annealing only the base region by means of a laser beam. CONSTITUTION:Impurity is selectively diffused in the surface of the Si substrate, which is to be the collector, on making the oxide film 2 a mask in order to form the base region 3 and the emitter region 4 that is in the region 3., Next, the radiations such as gamma-rays and beta-rays are applied to the entire surface of the substrate by using a radiocative isotope RI such as cobalt 60 in order to increase the switching speed in the collector side. After this, polycrystal Si layer 5 is put on the entire surface of the substrate, only the layer 5 on the base region 3 is removed from the substrate by a photoetching process, a pulse laser beam is applied to the region 3 through the exposed film 2 for an extremely short time on the order of 10 nanoseconds to anneal the region 3. In this way, the switching characteristic can be improved without the lowering of both hFE and noise characteristics. |
