| 摘要 |
PURPOSE:To obtain a single crystal semiconductor substrate proper to the semiconductor device, speed and dielectric resistance thereof are high, by forming a porous insulator layer, which is acquired by oxidizing a porous semiconductor layer, onto the substrate, shaping a single crystal semiconductor layer to one part of the surface and forming an insulator layer to the bottom and the side surface through heat treatment. CONSTITUTION:The P type single crystal Si substrate 1 is immersed in a 20-50wt% fluoric acid solution, and the bottom of the substrate 1 is connected to the anode side of a DC power supply and the cathode side of the power supply is connected to a platinum electrode immersed in the solution. Accordingly, the surface layer section of the substrate 1 is changed into the porous Si layer 2, the natural oxide film of the surface of the layer 2 is removed through heat treatment in vacuum while the layer 2 is turned into the porous insulator layer, the single crystal Si layer 4 is grown on the whole surface in an epitaxial shape, and the layer 4 is converted into a predetermined shape through etching while using a Si3N4 film 5 and a resist film 6 as masks. The film 6 is removed, the surface is thermally treated at 950 deg.C for approximately 150min., the insulator layer 7a is formed onto the back of the layer 4 by utilizing the faster speed of oxidation of the layer 2 while the thin insulator layer 7b is shaped onto the side surface of the layer 4, and an independent single crystal island region coated with the insulator layers is obtained on the substrate. |
