Evaluation of Plasma-Induced Damage by Medium-Energy Ion Scattering

Abstract

The plasma-induced Si surface damage in CF4+H2 and Ar plasmas which are used for the SiO2 contact hole etching and Si surface cleaning, respectively, have been studied by using the medium-energy ion scattering (MEIS) measurement. It was found that the Si damage induced by the CF4+H2 plasma treatment is relatively small compared with the Ar-ion-induced damage because of the formation of CF2 monomers on the Si surface. For the Ar plasma cleaning, the damage is increased with the self-bias. The small damage induced by Ar plasma at self-biases less than -80 V was detected by the MEIS. The MEIS results have been compared with electrical characteristics of Al/n-Si Schottky diodes for which the Si surface was Ar plasma cleaned. The leakage current and the barrier height of the Al/n-Si Schottky diodes exhibit good correlations with the MEIS data.