MANUFACTURE OF SEMICONDUCTOR ELEMENT

PURPOSE:To contrive the improvement of element characteristics and reliability by forming the shallow junction of a conductive region and reducing the noise by unnecessitating high-accuracy mask alignment by a method wherein a poly Si film having the same properties as the substrate Si is formed in the upper layer of the substrate. CONSTITUTION:An SiO2 film 11a and the poly Si film 13 having the same properties as the n type Si substrate 1 are formed on the substrate 1. A p type impurity is ion-implanted to an active base region 12. An Si3N4 film 15a, an SiO2 film 14a, an Si3N4 film 15b, and an SiO2 film 14b are formed and made as a mask, an oxide film 11b produced by oxidation of the Si film 13 formed by steam oxidation, and a base contact window and an emitter diffused window are formed at the same time. After removal of the films 15a, 15b, 14a, and 14b, a base contact region 17 and an emitter region 18 are formed by ion implantation of p type and n type impurities to each by the use of resist, and then by annealing. Finally, a base electrode 19 and an emitter electrode 20 are formed.