| 摘要 |
PURPOSE:To improve the sensitivity of optical ignition while ameliorating di/dt resisting quantity by forming a concave section, the maximum diameter of the bottom thereof is within the twice of the diffusion length of carriers in an adjacent base, to one part of an emitter layer of a light receiving section. CONSTITUTION:Gallium or aluminum is diffused as a dopant from a pair of N type silicon main surfaces 101, 102, a pE layer 1 and the pB layer 3 are formed simultaneously, and nE layers 4 and nEO layers 40 are diffused from the main surface 102 while using phosphorus as a dopant. The excessive nE layers are removed through a selective chemical etching method while a short-circuiting hole 7 and the concave sections 401 of the light receiving section region are shaped. The width W of the concave sections 401 is within the twice of the diffusion length L of carriers in the pB layer 3 at that time. |
