Method for producing transistor

Abstract

A method is provided for fabricating a first and second MOSFET transistors in different electrically isolated active areas of a semiconductor body, each one of the transistors having a plurality of layers. A first gate oxide layer and a first poly-crystalline silicon layer are deposited over the semiconductor body over the active areas. Said semiconductor body delineate the first and second active areas, thereby forming first delineated gate oxide layer and poly-crystalline silicon layers coextensive with the first active area. Material is deposited in said trenches to form the active area isolations, the active area isolations having a top surface above said semiconductor body. A masking layer is then formed over said first and second active areas and selective portions of it are removed to expose said second active area. A second gate oxide layer and a second poly-crystalline layer are formed, such second layer and second poly-crystalline layer being coextensive with the second active area. A first transistor and a second transistor are formed.

Description

technical field [0001] The present invention relates to methods of manufacturing transistors, namely Complementary Metal Oxide Field Effect Transistors (CMOS FETs). Background technique [0002] The cost and yield of the manufacturing process of semiconductor chips depends on various factors. One factor is the number of masks (mask layers) used during the process. An increase in the number of masks used in a process generally increases the cost of the process. Another factor is the extent to which the process uses self-aligning processing steps or misalignment tolerance structures. A misalignment tolerant structure is a structure that is manufactured with a high degree of misalignment tolerance from previously formed or subsequently formed structures. Clearly, the self-alignment step or misalignment tolerance structure increases the yield of the manufacturing process by reducing the number of unusable chips due to misalignment. Therefore, it is generally preferred to red...

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Problems solved by technology

Each transistor has multiple layers

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