MANUFACTURE OF HIGH REVERSE BLOCKING POWER DIODE

PURPOSE: To eliminate getter substance, to avoid corrosion of a semiconductor surface and to prolong the life of a carrier irrespective of diffusion depth by dropping a diffusion temperature to a desired one and generating a getter operation in a second process. CONSTITUTION: Boron is adhered to one of the double main faces of a silicon monocrystal disk-like semiconductor substrate 10 as doping substance and phosphorus is adhered to the other face as doping substance. In a first process, boron and phosphorus are diffused into the substrate 10 until they reach prescribed depth with a prescribed condition. In the condition, the diffusion temperature is 1265±C and diffusion time in an oxide atmosphere is thirty hours. In the following second process, diffusion is executed with the diffusion temperature of a value between 1050'C and 1150 deg.C, by which diffusion depth is not affected at all or not affected so much, namely, 1100 deg.C here for thirty hours. Thus, the getter operation for prolonging the life of the carrier is generated and the forward voltage of the diode is dropped in the substrate 10 in the process. Consequently, the life of the carrier can considerably be prolonged irrespective of the diffusion depth.