| 摘要 |
PURPOSE:To obtain an FET of short gate length, high withstanding voltage, low noise and good frequency characteristics by making a concave part on the surface of a semiconductor substrate when making a J-FET, forming a gate diffusion region here and thus restricting its lateral diffusion. CONSTITUTION:An N type layer 2 is epitaxially grown on a P<+> type Si substrate 1, and using an SiO2 film 3 as a mask, the exposed part of the layer 2 is etched off, and diffusion forming a P<+> type region 10 here, the layer separated into island regions. Next, an Si3N4 film 11 is coated all over the surface including the SiO2 film on the region 10 formed at this time, an opening 12 is made in these films, and further a concave part 8 is made in the exposed island region 2. Then forming a P<+> type gate region 9 here by ion implantation, covering the surface with an SiO2 film 14 and making an opening 15 in the previously formed laminated film, N<+> type source and drain regions 5 and 6 are diffusion formed respectively on both sides of the region 9. By so doing, mutual conductance for low frequencies is increased. |
