| 摘要 |
PURPOSE:To improve flatness and suppress the autodoping of impurity atoms from a high-concentration layer, by a method wherein an insulating film is formed on the surface of a substrate except for a semiconductor element forming region, and an epitaxially grown semiconductor layer lower in concentration than the substrate is formed in the semiconductor element forming region on the substrate by the epitaxial growth technique under a reduced pressure. CONSTITUTION:An oxide film 22 is formed on the surface of a P type high- concentration silicon substrate 21 by thermal oxidation. The part of the oxide film 22 in a predetermined region is removed by the photoetching technique, and a P type silicon epitaxial layer 23 of low concentration on the order of 20OMEGAcm is formed on the exposed surface of the substrate 21 under a reduced pressure. N type high-concentration diffused layers 24, 25 are formed as source and drain. Further, a gate 26 and electrodes 27, 28 of aluminum are provided on the surface to form an N-channel MOS semiconductor device. All the surface except for the predetermined portion is covered with the oxide film 22; therefore, the part of the silicon surface is small in area which contributes to autodoping in the autodoping is suppressed. |
