SEMICONDUCTOR DEVICE AND MANUFACTURE THEREOF

摘要

PURPOSE:To enable the minute forming with the high cut-off frequency regardless of the scale dividing errors of the mask by a method wherein the emitter region is formed through the intermediary of the multicrystal silicon film provided on the base region. CONSTITUTION:The oxide film 4 is formed on the n type epitaxial layer 3 on the p type substrate 1 provided with the n type embeddd region 2 while the window 16 is coated with the multicrystal Si film 17 and the nitride film 18. Said films 17 and 18 are removed excluding the region 19 to be the emitter and the impurity ion is inplanted through the window 16 to form the base region 20. Consequently the base width under said region 19 is made sharrow. The nitride film 18 is removed to expose the multicrystal Si film 17 to the atmosphere and the emitter region 11 is formed in the base region 20 through the intermediary of said film 17. Through these procedures. The minute forming of the sharrow emitter region and the base width with the high cut-off frequency is enabled regardless of the scale dividing errors of the mask.