Effects of irradiation temperature and dose on exfoliation of H+-implanted silicon carbide

H + implantation of SiC is the basis for a thin-film transfer process, which when combined with oxidation and hydrophilic wafer bonding, can be exploited to produce silicon carbide-on-insulator material useful as a wide-band-gap semiconductor. This thin-film transfer process has been successfully applied to Si to produce a commercial silicon-on-insulator material. The efficacy of hydrogen to produce thin-film separation was studied by investigation of H+-induced exfoliation in implanted SiC. Results showed that the onset and degree of exfoliation of SiC depends initially upon the concentration of implanted H+. However, the dose dependence of exfoliation exhibits a rather marked retrograde behavior. The degree of exfoliation eventually starts to decrease with increasing ion dose until exfoliation is completely suppressed. This behavior is attributed to a competition between the positive effects of hydrogen on exfoliation and the negative effects of ion-induced damage. Experiments were done to isolate the effects of the hydrogen–silicon chemistry from that of implant damage. Damage is reduced independently of H+ dosage by elevating the temperature of the SiC during implant in order to promote dynamic annealing. This will be shown to have a dramatic effect upon exfoliation. The “hot” implant lowers the H+ fluence required to affect thin-film separation, making the process more efficient, and producing SiC material with fewer defects.