| 摘要 |
PURPOSE:To improve the ohmic properties of an ohmic electrode while facilitating the control of the depth of a P-N junction by introducing an impurity changed into a reverse conduction type from the upper surface of one conduction type carrier multiplication layer formed onto an optical absorption layer or a carrier acceleration layer. CONSTITUTION:With a P-type region 6, Cd having a small diffusion coefficient is used as an impurity, and it is shaped in desired depth through a gas diffusion method. When Cd is employed as the impurity, a diffusion time is lengthened, thus easily controlling the depth of the P-type region 6, the depth of a P-N junction 10, then improving the yield that the P-N junction 10 is received in desired depth. Zn having a large diffusion coefficient is used as an impurity in a P-type contact region 11 and the region 11 is shaped through the gas diffusion method, and the ohmic properties of P-electrodes 8 are improved. Since the temperature of the diffusion of the latter is made lower than that of the diffusion of the former and the time of the diffusion of the latter is made shorter than that of the diffusion of the former, the depth of the P-N junction 10 formed by the diffusion of the former is not disturbed by the diffusion of the latter. |
