Improving field leakage by using a thin layer of nitride deposited by chemical vapor deposition

Abstract

A nitride layer is deposited over a field oxide layer used to separate transistors formed in a substrate, the nitride layer serving to decrease transistor current leakage. The nitride layer has a dense lattice, effectively blocking H+ and Na+ penetration from overlying layers into the field oxide. Positive ions such as H+ and Na+ penetrating into the field oxide layer cause a p-substrate under the field oxide layer to become inverted or act like an n-type substrate, creating leakage current between source and drain regions of transistors which the field oxide layer separates. When high transistor threshold voltages such as 12 volts or more are desired, the nitride layer provides a significant reduction in current leakage.

Dependencies are inferred from the claim text.