| 摘要 |
PURPOSE:To realize a GTO capable of a large peak turn-off current by a method wherein the cathode emitter forbidden band is designed to be thicker than a p-type base layer for the construction of a hetero-structure. CONSTITUTION:A hetero-structure design is employed wherein the forbidden band of a cathode emitter 1 is thicker than a p-type base layer 2. For a reduction in the resistance rhop of the p-type base layer 2, the impurity concentration of the cathode emitter 1 is lowered when impurity concentration is higher in the p-type base layer 2, which prevents VJ from reduction. With the cathode emitter 1 being thick in forbidden band, there is no reduction in the current amplification factor of an n-p-n transistor section or in Goff even when impurity concentration is lowered in the cathode emitter 1. A further increase in impurity concentration in an n-type base high-concentration layer 4 results in a reduction in the current amplification factor of a three-layer p-n-p transistor section built of a p-type anode emitter layer 5, the n-type base layer 3, and the p-type base layer 2, which will adversely affect GTO behavior. But such a difficulty may be avoided when a p-type anode emitter 5 is built into a hetero-structure with its forbidden band thicker than the n-type base 1. |
