Bell Telephone Laboratories

William Joshua Evans

Bernard T Murphy

Wesley Norman Grant

Roger Edwards

An integrated injection logic circuit cell structure and its fabrication are simplified. A pattern of oxide isolation regions is used to define, at least partially, the introduction of two types of impurities in such a way as to reduce the number of masking steps. Certain of these oxide regions do not penetrate through the conventional epitaxial layer, leaving a lateral buried path to serve as the base of a lateral injection transistor. A pattern of polycrystalline silicon containing impurities is used both as a diffusion source and an interconnection.

Integrated injection logic using oxide isolation

A method of making an oxide isolated integrated circuit structure is simplified by forming a first level metallization pattern without the conventional underlying insulating layer and without the need for restricting the size of the metallization to the size of the semiconductor regions to be contacted. Portions of the first level metallization pattern can extend on the oxide isolation region to contact two otherwise isolated semiconductor zones. Additionally, subsequent to the formation of the oxide isolation regions and the first level metallization, an intermediate dielectric masking pattern is formed so the combination of the first level metallization, the oxide isolation regions and the masking pattern defines zones for the introduction of impurities. Further, the masking pattern alone is used to provide contact holes for a subsequently formed second level metallization pattern.

Method for fabricating oxide isolated integrated circuits

A logic gate circuit includes parallel drive of an output transistor and an inverter transistor by an input transistor. The inverter transistor then drives an active pull-up transistor which improves switching speed. The parallel drive of the invention allows the use of the active pull-up transistor without requiring a change in circuit voltage levels.

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Berkeley Heights, NJ, United States of America

William Joshua Evans