| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that it is difficult to form a plurality of transistors having different threshold voltages on the same semiconductor substrate by adjusting the threshold voltages of the transistors to appropriate values in a completely depleted SOI transistor. SOLUTION: On the silicon active layer (=SOI layer) (of an SOI substrate 104), dummy gate patterns 111 and 112 are formed and, thereafter, gate grooves 130 and 132 are provided by removing the gate patterns 111 and 112. The threshold voltage of each transistor is adjusted by reducing the thickness of a portion constituting a channel region by etching the silicon active layer 103 in the gate grooves 130 and 132. Consequently, the degree of freedom for circuit design can be improved according to conditions. COPYRIGHT: (C)2004,JPO
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