| 摘要 |
PURPOSE:To contrive not to generate dispersion to the threshold voltage of depletion mode elements, by leaving neutral regions by controlling the impurity density, the thickness, etc. in at least one of an electron supply layer and a shielding layer. CONSTITUTION:A channel region 9 is formed on the surface of a channel layer 3 in the depletion mode element part D. Contact regions 101 and 102 reaching the channel region 9 are formed under output terminals 7D1 and 7D2. In the same manner as the enhancement mode element part E, an N type layer 6 is selectively removed, and accordingly a gate electrode 8D is formed on an exposed N type layer 5. The current is varied by impressing a negative voltage on this electrode 8D resulting in the variation of the thickness. Since a high electron mobility transistor (HEMT) of depletion mode unnecessitates the formation of a gate electrode on the shielding layer 6, the part is removed and can be provided on the exposed electron supply layer 5. Therefore, the threshold voltage of the depletion mode HEMT is made uniform. |
