| 摘要 |
PURPOSE:To enable the formation of a bipolar transistor and a MOS transistor of LDD structure on the same substrate, by a method wherein a sidewall composed of a second polycrystal attaching to the side surface of a gate electrode is utilized, by the etching method of a second polycrystal silicon layer. CONSTITUTION:A first polycrystal silicon layers 9-1-9-3, and gates 9'-1-9'-3 are formed in a MOS transistor forming region. A second polycrystal silicon layer covering a gate electrode part is formed in a bipolar transistor forming region. Then by patterning of anisotropic etching, a first sidewall (13-1-13-2) and a second sidewall (13'-1-13'-2) are formed on both surfaces of an emitter electrode 12 and the gate electrodes 9'-1-9'-3, via a silicon oxide film. Applying these side-walls to masks, prescribed impurity ion is implanted in a MOS transistor forming region to form a high concentration source region or a high concentration drain region. Thereby, a transistor of LDD (Lightly Doped Drain) structure can be formed on the same substrate as a bipolar transistor.
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