| 摘要 |
PURPOSE:To form a plural kind of bipolar transistors, etc. so that each of them has desired characteristics without increasing an impurity introducing process by introducing an impurity under the state in which a nitride film used for selectively oxidizing a semiconductor substrate is removed in one base region or gate region and left on the other region. CONSTITUTION:N<+> buried layers 2, N type epitaxial layers 3 and an insulating region 4 are formed to a P type silicon substrate 1, and oxide films 6 are shaped while using nitride films 5 as masks. A P type impurity is introduced while using resists 8, etc. as masks under the state in which the nitride film 5-1 on a base region in a transistor 100 of high dielectric resistance and low hFE is removed and the nitride film 5-2 on a base region in a transistor 200 as an IIL is left to form base regions 9, 9', and the whole quantity of the impurity in both base regions and the depth of collector-base junctions are each changed by the same impurity introducing process. When the nitride film 5 is removed and polycrystalline silicon layers 10 are formed and an emitter 11, a base 9, a collector 12 and an electrode are shaped, a semiconductor device containing two kinds of N-P-N bipolar transistors, characteristics thereof mutually differ, can be manufactured. |
