Plasma Etching Induced Damage to Strained Si/SiGe/Si heterostructure

Dry etching can deteriously affect strained SiGe films by initiating misfit strain discontinuity in the film as well as in the interface. Annealing behavior of RIE induced defects is reported in this paper. Transmission electron microscopic investigations indicate creation of dislocation loops (having size in the range 10-14 A) due to ion bombardment stress. Deep Level Transient Spectroscopic measurements reveal defect levels at 0.62, 0.57, 0.56 and 0.44 eV for the dry etched samples annealed at 650, 700, 750 and 800 /spl deg/C respectively. Size of the dislocation loops estimated from the DLTS results are in good agreement with that obtained from the TEM measurements.