| 摘要 |
PURPOSE:To obtain a transistor with small junction capacitance and enabling high speed switching by a method wherein the junction capacitance of the lateral extension of each junction is reduced to make the junction effective. CONSTITUTION:On a silicon substrate 1 formed by a normal bypolar, embedded process, a trapezoidal epitaxial island 5 or the side of the island etching processed comprising three layered substrate structure consisting of an epitaxial layer 2, an embedded layer 3 and a nitride film 4 is inversely tappered. Then an insulating oxide film 6 is formed by means of oxidizing within an oxidative atmosphere while the angle theta made by the surface of an epitaxial layer and the side of the oxide film may exceed 90 deg. by means of properly selecting the said inversely tapered angle to reduce the junction area. Through these procedures, the junction capacity of the junction 7 of the emitter base and the junction 8 of the collector may be reduced. |
