| 摘要 |
PROBLEM TO BE SOLVED: To easily attain the linearity of desired variable capacitance for control voltage and also attain sufficiently wide variable range of capacitance in the semiconductor device including a silicon layer, an oxide film and a semiconductor substrate, or a semiconductor device having the SOI(Silicon on Insulator) structure where these elements are laminated. SOLUTION: In the semiconductor device, an oxide film is provided at the upper part of the semiconductor substrate, and a silicon active layer is provided at the upper part thereof. A variable capacitance diode in which a plurality of impurity concentration regions are formed is formed on this silicon active layer. The silicon active layer is also provided with a diffusing layer having an impurity profile which gradually changes in the lateral direction. Employment of this structure enables constitution of the variable capacitance diode even when the silicon layer having thin surface is included like the semiconductor device of the SOI structure. The variable capacitance diode of this structure is capable of improving the linearity of variable capacitance for control voltage. COPYRIGHT: (C)2005,JPO&NCIPI
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