HI-H2 vapor etch for low temperature silicon epitaxial manufacturing



Etching of semiconductor silicon slices at 998°C with HI-H2 mixtures was developed to the level that practical etch rates (≥ 0.1 μm/min) and smoothness of surfaces were obtained in a manufacturing type reactor without the addition of HF or He. Such a low temperature etch is expected to lead to improved device characteristics, mainly because of more sharply defined junction surfaces.

Using deposition at 998°C on very clean slices as a testing method, two sources of impurities that cause stacking faults in the deposition layers were identified and eliminated. These were the polypropylene vessel used in the slice cleanup procedure, and the hydrogen peroxide used in conjunction with sulfuric acid in the primary cleaning step.