Some aspects of alloying and crystallization of amorphous silicon germanium

Abstract EN

A series of a-S il-xGex thin films have been deposited on two type of substrates; micro glass and silicon wafer, using vacuum thermal evaporation technique.

The effects of annealing temperature and germanium quantity on the structural and electrical properties of the prepared films have been studied, while the rest of deposition parameters(thickness, deposition rate vacuum pressure and substrate temperature) are fixed throughout the testes.

Using x-ray spectrometer, it is found that there is a difference in the perma nium quantity between the calculated values of the prepared alloys before evaporation and the values of the germanium in the deposited films.

The results obtained using x-ray diffraction technique showed that all fabricated samples were amorphous at the beginning.

The pol y crystalline structure is initiated at annealing temperature equal to 600 deg.

for the samples deposited on glass substrate, but the crystalline structure is di stored above this temperature, While the crystalline structure of the samples fabricated on Si-wafer becomes more pronounced at higher annealing temperature.

Surface I-V characteristics share the proves that higher annealing temperature and germanium quantity shows higher degree of crystallization and higher forward current and small reverse current through the heterojunction.