DEPTH PROFILE ANALYSIS OF AMORPHOUS/MICROCRYSTALLINE SI SOLAR CELLS BY SECONDARY NEUTRAL MASS SPECTROSCOPY

摘要

Quantitative depth profile analysis performed by a Secondary Neutral Mass Spectrometer (SNMS) is a promising method to investigate the layer structure of solar cells. SNMS is a destructive analysis technique based on the measurement of secondary neutral particles sputtered from the surface of a sample. The sputtering can be performed by an ion beam. While the emitted secondary ions can be analyzed by Secondary Ion Mass Spectrometry (SIMS), the neutral atoms can be analyzed by SNMS. In the case of insulating samples the surface roughness and surface charge accumulation can cause a serious problem during depth profile analyses. A high frequency mode developed to electron-gas SNMS in combination with a conducting metallic mesh placed on the sample surface can prevent this charge accumulation. TCO layers have high surface roughness, because a special surface texture in order to maximize the solar cell efficiency. We have applied these methods to depth profile analysis of TCO layers and n-i-p: Si diodes.