ON THE NEAR MID GAP DONOR LEVEL-EL-2 IN GaAs

Abstract

The performance of every device is controlled by impurities, defects, vacancies and their complexes in semiconductors used in fabrication. Levels lying deep in forbidden energy gap can play a crucially active part in device operation. In the present work3a novel technique Deep level transient spectroscopy (DLTS) for characterization of deep levels has been presented. From the collection of data from literature,an attempt has been made to find out Physio-chemical origin of the EL-2 level in GaAs lying 0.83 eV below Ec. It has been found out that this level has been associated with arsenic antisite defect, Also theoretical aspects and experimental work on Metal-semiconductor contacts has been presented. Work has been carried out with Aluminium metal on Silicon for both ohmic and rectifying contacts. Indium and Gold have been used on Gallium Arsenide for ohmic and rectifying contacts. From C-V measurements carrier concentration (N) and barrier height (0b) has been found out ( For silicon N= 8.95 x 1016m3, Ob = 0.806 eV. For Gallium Arsenide Nd= 2.1 x 1022m-3, Ob = 0.73 eV)