水素化アモルファスシリコンの表面酸化起因真性応力の分子動力学解析

Abstract

It was reported that the lack of the structural stability of semiconductor silicon micro-pattern induced the lateral undulation buckling. Our previous report revealed that the intrinsic stress of the oxide film on the surface of amorphous silicon produced the compressive stress which induces the buckling failure. However, actual amorphous silicon contains hydrogen atoms. Therefore, in this study, we realize the surface oxide film fabrication on hydrogenated amorphous silicon and clarify the relationship between hydrogen concentration and intrinsic stress due to surface oxidation. As a result, regardless the hydrogen concentration, surface oxide layer contains no hydrogen atoms. In addition, it is found that the intrinsic stress is generated in the sub-oxide layer where oxidation process is not completed. As the hydrogen concentration increases, the integral value of the compressive stress decreases linearly. The stress decreases about 30 % when the hydrogen concentration reaches 25 at%. Decrease in the stress would be caused by the sparse silicon structure due to hydrogen atoms and resulting release of the strain due to surface oxidation.