Silicon surface cleaning by oxidation with electron cyclotron resonance oxygen plasma after contact hole dry etching

Abstract

A simple technique for cleaning a silicon surface after contact hole etching is proposed for obtaining stable p+ silicon contact characteristics for very large scale integrated interconnections. The contaminated layer of the silicon contact surface after dry etching is first oxidized with electron cyclotron resonance (ECR) oxygen plasma and then the surface oxide is removed by wet etching with diluted HF. X-ray photoemission spectroscopy and secondary-ion-mass spectroscopy analyses show that one of the main reasons for the instability of the p+ silicon contact is fluorine contamination, which can be removed controllably by ECR oxygen plasma treatment followed by wet etching. This surface oxidation technique with ECR oxygen plasma is, therefore, an effective way to obtain stable and low-resistance p+ contact characteristics.