RAPID CHEMOGRAPHY OF POROUS SILICON UNDERGOING HYDROLYSIS

Highly porous silicon reacts with water vapor in the air to create ima ges on photographic plates within seconds. It is demonstrated that thi s process, known as chemography, can be used diagnostically to reveal inhomogeneity in porous silicon layers that is not always detectable b y optical or electron microscopy. It is suggested that many dried high ly porous semiconductors may constitute a significant health hazard ow ing to the liberation of high concentrations of toxic hydrides through hydrolysis.