| 摘要 |
PURPOSE:To prevent the erroneous operation of alpha-ray emission of an MOSLSI by epitaxially growing a high specific resistance layer of low impurity density on a low resistance Si substrate and electrically isolating the epitaxial layer with a selectively oxidized film reaching the low resistance substrate. CONSTITUTION:A P type epitaxial layer 2 having, for example, 10OMEGAcm is grown in 5mum on a P type substrate 1 having, for example, 0.05OMEGAcm. Then, with Si intrided film as a mask, a field oxidized film 3 is formed by a selective oxidation method. The film 3 is formed in the depth reaching the substrate 1, but when a high density region (channel stopping layer) 4 is formed between the film and the substrate 1, the film 3 may e reduced in thickness. Subsequently, an MOSFET or the like is formed in an ordinary step in the layer 2. In this manner, minority carrier generated in the substrate 1 by alpha-ray emission is mostly recombined in the substrate due to short diffusion length, thereby enabling to eliminate the influence to the element characteristics. |
