Multi-plasma nitridation process for a gate dielectric

摘要

A gate dielectric can be formed by depositing a first silicon oxide material by a first atomic layer deposition process. The thickness of the first silicon oxide material is selected to correspond to at least 10 deposition cycles of the first atomic layer deposition process. The first silicon oxide material is converted into a first silicon oxynitride material by a first plasma nitridation process. A second silicon oxide material is subsequently deposited by a second atomic layer deposition process. The second silicon oxide material is converted into a second silicon oxynitride material by a second plasma nitridation process. Multiple repetitions of the atomic layer deposition process and the plasma nitridation process provides a silicon oxynitride material having a ratio of nitrogen atoms to oxygen atoms greater than 1/3, which can be advantageously employed to reduce the leakage current through a gate dielectric.

主权项

1. A method of forming a semiconductor structure comprising:
providing a semiconductor substrate including a first top semiconductor portion and a second top semiconductor portion; simultaneously converting an upper portion of said first top semiconductor portion into a first semiconductor oxynitride portion and an upper portion of said second top semiconductor portion into a second semiconductor oxynitride portion by performing an oxynitration anneal, wherein said first semiconductor oxynitride portion and said second semiconductor oxynitride portion contain from 2 atomic % to 10 atomic % nitrogen; depositing a first silicon oxide material over said first and second semiconductor oxynitride portions by a first atomic layer deposition process; converting said first silicon oxide material into a first silicon oxynitride material employing at least a first plasma nitridation process; depositing a second silicon oxide material on said first silicon oxynitride material by a second atomic layer deposition process; and converting said second silicon oxide material into a second silicon oxynitride material by a second plasma nitridation process, wherein a ratio of nitrogen atoms to oxygen atoms in a stack of said first and second silicon oxynitride materials is greater than 1/3.