| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem that the fabrication process is complicated and the etching accuracy is lowered when a plurality of transistors, each having a so-called metal gate electrode layer and a different threshold voltage, are provided on the same semiconductor substrate and thereby it is difficult to increase the degree of freedom in the circuit design. SOLUTION: Polysilicon gate layers 110 and 111, introduced with a quantity of metal material (e.g. indium (In), antimony (Sb)) exceeding the solubility limit in silicon, are formed on a silicon substrate 100 through an aluminum oxide film 102 (= gate oxide film) Subsequently, an indium (In) deposition layer 118 and an antimony (Sb) deposition layer 119 are formed simultaneously by heat treatment at the interface with the aluminum oxide film (Al<SB>2</SB>O<SB>3</SB>) 102. Transistors having a different threshold voltage can be formed on the silicon substrate 100 by providing gate electrode layers 120 and 121 having a different work function. COPYRIGHT: (C)2004,JPO
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