| 摘要 |
PROBLEM TO BE SOLVED: To form a low resistance contact region in a self alignment manner without use of an exclusive mask on a surface layer of a source region or a p well region of a MOSFET, etc. SOLUTION: An insulating film 4 is formed on the surface of a p well region 1 and is selectively removed, and an n source region 2 is formed with a high concentration arsenic atom on a surface layer of a p well region 2. Further, ion is implanted by forcing a high concentration boron atom to pass through the entire surface of insulating films 4a, 4b to be shallow from the n source region 2, and a high concentration boron diffusion region 3 is formed on a surface layer of the p well region 1 with the aid of a heat treatment thereafter, and ion is implanted by forcing a high concentration arsenic atom to pass through the entire surface of the insulating film 4b but preventing the atom from passing through the insulating film 4a. A high concentration arsenic diffusion region 15 is formed on a surface layer of the n source region 2 with a heat treatment thereafter, and an oxide film is deposited into a thick oxide film 40. Further, the insulating films on the boron diffusion region 3 surrounded by the n source region 2 and on the n source region 2 are selectively removed, and the same metal film is formed on an exposed surface of the n source region 2 and on an exposed surface of the boron diffusion region and on the surfaces of the insulating films. |
