| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve such characteristics as the capacity increases linearly and significantly for a voltage change in a narrow range. <P>SOLUTION: In a varactor diode 50 formed by etching a layer grown epitaxially on an InP semiconductor substrate 21, the layer grown epitaxially on an InP semiconductor substrate 21 comprises: a p-region 50d composed of a material heavily doped with p-type impurities and having a band-gap energy lower than that of the semiconductor substrate 21; an I-region 50c in contact with a surface of the p-region 50d close to the semiconductor substrate 21 and composed of a material that is not doped with impurities or a lightly doped material; and an n-region 50b in contact with a surface of the I-region 50c close to the semiconductor substrate 21, and composed of a material moderately or heavily doped with n-type impurities and having a band-gap energy higher than that of the semiconductor substrate 21, and in which concentration reduction part (54-57) having concentration decreasing gradually from the I-region 50c toward the semiconductor substrate 21 side is included. <P>COPYRIGHT: (C)2013,JPO&INPIT |
