| 摘要 |
PURPOSE:To reduce current density, and to obtain the GTO having the large controllable current by a method wherein the shape of an emitter on the side adjoining to a gate is devised to divide current concentration just before turning off into two parts. CONSTITUTION:After a pE layer 4, an nB layer 1, a pB layer 2, and an nE layer 5 are laminated according to the prescribed form, a part of the surface of the pB layer 2 other than the part of the nE layer 6 is etched to be removed, and the nE layer 5 is made to protrude from the pB layer 2. A concave part 10 is provided at the center of the layer 5, an SiO2 film 11 to cover the inside face and an SiO2 film 6 for protection of p-n junction are formed selectively, and Al electrodes 7-9 for the cathode, the gate and the anode are fixed. The concave part 10 is provided at the position not to overlap completely with the pE layer 4 when the concave part is projected to the main surface on the anode side. At this construction, when the gate electrode 8 is negatively biased in relation to the cathode 7 making the anode electrode 9 to positive, because the layer 5 directly under the concave part 10 is made thin and has laterally directional resistance R, the anode current to concentrate to the center of the directly under part is pushed back to be divided into two parts to both sides, current density just before turning off is reduced by half, heat generation is reduced to 1/4, and the controllable current becomes simply to two times. |
