US 6,518,146 B1 · Semiconductor device structure and method for forming

Abstract

A semiconductor device has both a logic section and a non-volatile memory (NVM) section. Transistors in both sections are separated by trench isolation. The logic isolation has narrower trenches than NVM trenches and both types of trenches have corners at the tops thereof. The trenches are lined by growing an oxide that is necessarily to take care of the plasma damage of the substrate, which is preferably silicon, that occurs during the formation of the trenches. These oxide liners are grown to a greater thickness in the NVM trenches than in the logic trenches to obtain a greater degree of corner rounding in the NVM trenches. This growth differential is achieved by selectively implanting the NVM trenches with a species that speeds oxide growth or selectively implanting the logic trenches with a species that retards oxide growth. As a further alternative, the NVM trenches can be implanted with a growth enhancing species and the logic trenches with a retarding species.

Claims21

Dependent claims

A method for forming a semiconductor device structure in a semiconductor layer, comprising:

forming a first trench of a first width and a first corner and forming a second trench of a second width and a second corner, the first width differing from the second width;
forming a mask overlying the second trench;
creating a modifying layer that modifies oxidation rate of exposed portions of the semiconductor device structure not covered by the mask;
removing the mask;
and
thermally growing an insulating layer on the semiconductor structure to form an insulated first trench and an insulated second trench.

3 more elements

Dependencies are inferred from the claim text.

Semiconductor device structure and method for forming

Life of this patent

Semiconductor device structure and method for forming

Life of this patent

Abstract

Claims21