| 摘要 |
1,104,767. Insulated gate field effect transistors. FAIRCHILD CAMERA & INSTRUMENT CORPORATION. 14 Feb., 1967 [1 July, 1966], No. 7133/67. Heading H1K. In an insulated gate field effect transistor a dielectric layer with a relatively low surface charge density is provided over the channel region and a dielectric layer of higher surface charge density elsewhere. In the embodiment, Fig. 2, which is otherwise of conventional structure, the silicon oxide dielectric 20 over the channel is formed, after removal of the oxide layers used in diffusing the source and drain regions, by thermal growth in a dry atmosphere at 1200‹ C. or by anodic growth or vapour deposition followed by heating at 750-900‹ C. An oxide layer of higher surface charge density is subsequently formed over the remainder of the silicon body by a low temperature process such as anodization or vapour deposition. In an alternative form silicon oxide is used as the gate dielectric while the rest of the body is covered with silicon nitride. In any case the dielectric is made thinner over the channel than elsewhere. This measure and the use of the different surface charge density dielectrics reduce the risk of uncontrollable source-drain current paths being formed.
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