Electroluminescent device in silicon on sapphire

摘要

Electroluminescent devices are formed on a transparent sapphire substrate as follows. Crystalline silicon is formed on the sapphire substrate and patterned into a mesa. An electrode of, for example, titanium silicide, is formed in the silicon around the mesa, and an electrically insulating layer is formed over the electrode. The crystalline silicon is exposed on the mesa, and a porous silicon layer is formed on the crystalline silicon. An electrode made of aluminum, for example, is formed on the porous silicon layer. This electrode need not be transparent. An outer insulating layer may be formed on the aluminum electrode and additional electrodes may be formed on and through the outer insulating layer to make electrical contact with the titanium silicide and aluminum electrodes, respectively. A voltage source may be connected to the electrodes to pass a current through the porous silicon to cause light to be emitted from the porous silicon through the sapphire substrate.