The effect of additional O+ implantation upon the standard separation-by-implantation of SIMOX structures was analyzed, with regard to inherent defects, by means of electron spin resonance. The defects which were monitored included the E’ and E’ variants of the O-deficiency centers in the buried oxide layer, and the probably O-related shallow donor centers in buried interfacial Si layers. The E’ generation sensitivity depth profiles were mapped by using etching back, combined with E’ generation by exposure to a direct-current Ar glow discharge. A major result was that additional O implantation significantly reduced the E’ generation sensitivity (precursor sites) uniformly over all of the buried oxide layer. This reduction was about 2 times greater for E’ than for E’. On the other hand, the shallow donor centers increased by a factor of up to 6. It was concluded that the defects which were inherent to the SIMOX formation process were incompletely removed by post-implantation annealing at 1100C.

K.Vanheusden, A.Stesmans: Applied Physics Letters, 1995, 67[10], 1399-401