Electroluminescence and Photoluminescence from Microporous Silicon p-n Junctions

A novel immersion scanning technique for making microporous silicon has been successfully applied to blank and lithographically patterned Si substrates. The advantages of the method lie in its simplicity, speed of fabrication, and adaptability to large and odd-size substrates. The photoluminescence (PL) intensity of porous silicon shows a steady decrease between 200 and 2 K and this behavior is fully reversible. Thermal desorption spectroscopy on microporous Si shows a classic hydrogen desorption spectrum which coincides with a quenching of the PL intensity. Under constant excitation, a degradation of PL intensity occurs in oxygen and wet nitrogen but is only partially reversible in dry N2. Microporous Si p~n junctions exhibiting normal /-F characteristics have been successfully fabricated with standard Si very large scale integrated processes. Visible light emission under forward bias is detected which increases linearly in intensity with input current. This is the first observation of electroluminescence in the visible region from microporous Si p-n junctions. © 1993, American Vacuum Society. All rights reserved.