Relaxation of Strained SiGe on Insulator by Direct Wafer Bonding

Strained SiGe was bonded to silicon dioxide by direct wafer bonding and Smart-cut technique. Strained SiGe with a graded 20%-30% Ge concentration was deposited by RTCVD on (100) Si to a thickness between 300nm to 350nm. H 2 + for wafer splitting was implanted at an energy varied from 40 keV to 150 keV and a dose between 2.5E16 and 4.5E16 ions/cm 2 . SiGe relaxation was found to depend on wafer split temperature, and on post-split annealing temperature. SiGe relaxation of greater than 80% was observed after wafer splitting and annealing. Was it from gliding of a SiGe film weakly bonded to an oxide surface? In order to determine the relaxation mechanism, samples with different film structure were prepared. The films were then annealed at various temperatures. Some film showed a high degree of relaxation, and some showed minimal relaxation, depending mostly on hydrogen implant depth. The results indicated that the generation of dislocation is the possible cause of SiGe relaxation.