Semiconductor integrated circuit device

A semiconductor integrated circuit device comprising:

• a semiconductor polycrystalline substrate having first and second principal surfaces on opposite sides of said polycrystalline substrate;
• a semiconductor monocrystalline region formed in said semiconductor polycrystalline substrate to extend from the first principal surface of said substrate to the second principal surface thereof, said semiconductor monocrystalline region having a first principal surface formed in the first principal surface of said polycrystalline substrate and a second principal surface formed in the second principal surface of the polycrystalline substrate;
• at least one semiconductor monocrystalline island formed in said semiconductor polycrystalline substrate adjacent to said monocrystalline region, said at least one monocrystalline island having a principal surface formed in said first principal surface of said polycrystalline substrate;
• and
• a dielectric film formed between said at least one semiconductor monocrystalline island and said semiconductor polycrystalline substrate to isolate said at least one semiconductor monocrystalline island from said polycrystalline substrate and said monocrystalline region.