| 摘要 |
PURPOSE:To secure the difference in work functions of the superposition of layers and threshold voltage difference of MOSFET as well as to constitute the gate electrode of an MISFET (metal insulating semiconductor field effect treansistor) with a polyside film by a method wherein n-type and p-type gate electrodes are constituted by superposing a silicon film of the prescribed film thickness and a high melting point metal silicide film. CONSTITUTION:In the CODEC (code-decoder) having a reference voltage generating circuit composed of MISFET Qn1 and Qn2 of an n-type gate electrodes 6, both electrodes 6 and 6 are composed of a polycrystalline silicon film 6A or 6B, having the film thickness with which both gate electrodes 6 can be maintained at the difference in work functions of 1.1-1.7V, and a high melting point metal silicide film 6C. As a result, the difference in threshold voltage of 1.1-1.7V between the MISFET Qn1 and Qn2 can be maintained even when the high melting point metal silicide film 6C (polysilicide film structure) is used. Also, the impurities to be introduced into the polycrystalline silicon film 6A or 6B can be diffused uniformly by forming the silicon films 6A and 6B in the thickness same as that of the silicide film 6C or thicker than that. |
