Data Analysis Technique of Atomic Force Microscopy for Atomically Flat Silicon Surfaces

Abstract

A data analysis technology of atomic force microscopy for atomically flat silicon surfaces has been developed. Atomically flat silicon-surfaces composed of atomic terraces and steps are obtained on (100) orientation 200 mm diameter wafers by annealing in pure argon ambience at 1,200°C for 30 minutes. Atomically flat silicon surfaces are lead to improve the MOS inversion layer mobility and current drivability of MOSFETs and to decrease the fluctuations in electrical characteristics of MOSFETs. It is important to realize the technology that evaluates the flatness and the uniformity of atomically flat silicon surfaces. The off direction angle is calculated by using two straight edge lines selected from measurement data. And the off angle is calculated from average atomic terrace width under assumption that height difference between neighboring terraces is equal to the step height, 0.135 nm, of (100) silicon surface. The analyzing of flatness of each terrace can be realized by converting the measurement data using the off direction angle and the off angle. And, the average roughness of each terrace is about 0.017-0.023 nm. Therefore, the roughness and the uniformity of each terrace can be evaluated by this proposed technique.