Use of a partial local density of states calculation to characterize the Auger electron Si-L2,3 VV transitions of thin oxide layers

The line shape of the Si-L2,3 VV Auger spectrum is to a first approximation equal to the sum of the convolution products of the partial local density of states (pLDOS), each weighted by the two electron Auger matrix elements and the escape depth. Semiempirical quantum chemical cluster calculations have been used to calculate the pLDOS of SiOx (x=0, 0.5, 1, 1.5, 2) from which the line shape in the derivative mode [dN(E)/dE] could be obtained by using the angular momentum selection rules of Feibelman et al., neglecting the structure in the radial two electron Auger matrix elements. Within this approximation we were able to interpret peaks in the measured Si-L2,3 VV Auger line shape of the initial oxidized silicon surfaces (100, 111, 110) and the fully oxidized Si(100) in the derivative mode in terms of local chemical bonding.