The Effects of Damage on Hydrogen-Implant-Induced Thin-Film Separation from Bulk Silicon Carbide

Exfoliation of SiC by hydrogen implantation and subsequent annealing forms the basis for a thi n-fiim separation process ~vhichqwhen combined with hydrophilic wafer bonding. can be exploited to produce siIicon-carbide-cm-insulator, SiCOI. Sic thin films produced by this process exhibit unacceptably high resistivity because defects generated by the implant neutralize electrical carriers. Separation occurs because of chemical interaction of hydrogen with dan:l ing bonds within microvoids created by the implant, and physical stresses due to gas-pressure effects during post-implant anneal. Experimental results show that exfoliation of SiC is dependent upon the concentration of implanted hydrogen, bm the damage generated by the implant approaches a point when exfoi iation is, in fact, retarded. This is attributed to excessive damage at the projected range of the implant which inhibits physical processes of implantinduced cleaving, Damage is controlled independently of hydrogen dosage by elevating the temperature of the.SiC during implant in order to promote dynamic annealing. The resulting decrease in damage is thought to promote growth of micro-cracks which form a continuous cleave. Channeled H+ implantation enhances the cleaving process while simultaneously minimizing residual damage within the separated film. It is shown that high-temperature irradiation and channeling each reduces the hydrogen fluence required to ailect separation of a thin fi~mand resuks in a lower concentration of defects. This increases the potential for producing SiCOl which is sufficiently flee ofdefeets and, thus, more easily electrically activated,