| 摘要 |
PURPOSE:To enable to arbitrarily set accurately the threshold voltage of an FET by the externally applied voltage by providing a buffer region only directly under an active region which becomes a channel between source and drain regions formed in a compound semiconductor substrate. CONSTITUTION:To activate ion implanted layers 26, 27, 30 after removing a silicon nitrided film 22 and a photoresist 28, a heat treatment is performed. Thus, the layers 26, 27, 30 respectively become source, drain region and channel region. A silicon nitrided film 31 is then formed newly by a plasma CVD method, a photoresist pattern 32 is formed thereon, a hole 22 for forming a buffer layer is formed by a photographic step, and a P type region is formed as a buffer layer 34 by using an ion implantation method. Then, after removing the pattern 32, a heat treatment is executed to activate the layer 34. Photoresist is rotatably coated on the overall surface, the photoresist is opened as desired, and a necessary electrode material is deposited. |
