| 摘要 |
To obtain a device in which a buffer leak on a GaN substrate is reduced. In an HEMT device of the present invention, n-GaN (n-type GaN wafer) is used as a substrate 11. A non-doped AlpGa1-pN layer with non-uniform composition p is formed on the substrate 11 as a buffer layer 12. On the buffer layer 12, a channel layer 13 formed of semi-insulating GaN and an electron supply layer 14 formed of n-AlGaN are sequentially formed. In a composition of the buffer layer 12, a region (substrate connection region 121) where the value of p is set to 0 (p=0) (GaN) is formed on the lower end side, and a region (active layer connection region 122) where the value of p is also set to 0 (p=0) (GaN) is formed on the upper end side (channel layer 13 side). A region (high Al composition region 123) where the value of p is set to 1 (p=1) (AlN) is formed between the substrate connection region 121 and active layer connection region 122. The resistivity of the high Al composition region 123 is the highest in the buffer layer.
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