Patent ID: 7564073

Claim:
A semiconductor integrated circuit comprising: a single substrate; a normal complementary MOS transistor comprising ordinary MOS transistors each having a basic structure including a metal, an oxide and a semiconductor, the semiconductor consisting of a single semiconductor; and a heterojunction complementary MOS transistor comprising heterojunction MOS transistors each having said basic structure, the semiconductor of said basic structure consisting of different semiconductors forming a heterojunction, wherein: one or more such normal complementary MOS transistors and one or more such heterojunction complementary MOS transistors are formed on the single substrate; a portion of each of the heterojunction MOS transistors including the heterojunction is epitaxially grown on the substrate; a under surface of the epitaxially grown portion of each of the heterojunction MOS transistors and a under surface of a gate insulator of each of the ordinary MOS transistors are located at substantially equal depth in a direction along the thickness of the substrate, the epitaxially grown portion of each of the heterojunction MOS transistors includes a buffer layer, a heterojunction layer and a cap layer, which are sequentially epitaxially grown on the substrate in a thickness direction thereof and made of the semiconductor; and a under surface of the buffer layer and the under surface of the gate insulator of each of the ordinary MOS transistors are located at substantially equal depth in the direction along the thickness of the substrate.