| 摘要 |
PURPOSE:To prevent the leaving of a mixing layer in a finished product even when some N<+> mixes in an intermediate process by executing a high- concentration diffusion process first, lapping off one surface and executing a low-concentration diffusion process. CONSTITUTION:Phosphorus in approximately several mum is diffused to an N type silicon substrate 1 to form high-concentration diffusion layer 3 on both surfaces. An arbitrary surface is lapped off by using Al2O3 powder in cutting allowance of 10mum or more, and one high-concentration diffusion layer 3 is removed. Oxide films 4 are formed onto both surfaces, and a PB diffusion layer 2 is obtained by using Ga2O3. The diffusion process is executed for several dozen hr, and the N<+> layer 3 acquired by the first diffusion process is shaped in size deeper than the PB layer 2 through the diffusion process. Surface concentration extends over a value such as approximately 10<18>/cm<3> or less and junction depth takes a value such as 50mum in the PB layer 2, and surface concentration takes a value such as 5X10<20>/cm<3> and junction depth a value such as 55mum in the N<+> layer 3. |
