SEMICONDUCTOR ELEMENT

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PROBLEM TO BE SOLVED : To provide a semiconductor element for reducing influence of Fermi level of a substrate. SOLUTION : A buffer layer 2 is formed in various kinds and concentrations of a dopant by using a semiconductor material identical to the semiconductor substrate 1 on one surface of the same semiconductor substrate 1. The semiconductor layers 3a, 3b are formed to local areas on the buffer layer 2, and a channel layer 4 is formed in the dopant concentration lower than the semiconductor layers 3a, 3b using the same semiconductor material as the semiconductor substrate 1 on the opposing edges of the semiconductor layers 3a, 3b, or between the opposing edges thereof. In this case, thickness D (nm) of the buffer layer 2 should be within the range expressed by the formula obtained from a difference V(eV) between the Fermi level of the semiconductor substrate 1 and that of the channel layer 4, concentration NS(m-3) of effective donor of the semiconductor substrate 1 or concentration of effective acceptor, concentration NB(m-3) of the effective donor of buffer layer 2 or concentration of the effective acceptor, a channel length L (m), rare charge e, a specific dielectric coefficient εBof buffer layer 2, and a dielectric constant ε0of vacuum. COPYRIGHT : (C)2007, JPO&INPIT