Gettering of Cu by microcavities in bonded/ion-cut silicon-on-insulator and separation by implantation of oxygen

Microcavities formed by H+ and He+ implantation and subsequent annealing ar e effective gettering sites for transition metal impurities in silicon. How ever, gettering in silicon-on-insulator (SOI) materials is quite different from that in silicon. In this work, we investigate the gettering of Cu to t hese microcavities in silicon, separation by implantation of oxygen (SIMOX) and bonded/ion-cut SOI wafers. Our data indicate that He+ implantation in the high dose regime (0.2-1 x 10(17) cm(-2)) creates a wide band of microca vities near the projected range without causing blistering on the sample su rface. On the other hand, the implantation dose of H+ needed for stable mic rocavity formation is relatively narrow (3-4 x 10(16) cm(-2)), and this val ue is related to the projected range. The different behavior of H and He in silicon is discussed and He implantation is more desirable with regard to impurity gettering. Cu is implanted into the surface region of the Si and S OI samples, followed by annealing at 700 and 1000 degrees C. Our results in dicate that the microcavities can effectively getter a high dose of Cu (2.5 x 10(15) cm(-2)) at 700 degrees C in bulk Si wafer, but higher temperature annealing is needed for the effective gettering in SIMOX. Gettering of Cu by the intrinsic defects at or beneath the buried oxide interface of the SI MOX is observed at 700 degrees C, but no trapped impurities are observed af ter 1000 degrees C annealing in the samples in the presence of microcavitie s. Almost all of the 1 x 10(14) cm(-2) Cu implanted into the Si overlayer o f the bonded/ion-cut SOI diffuse through the thermally grown oxide layer an d are captured by the cavities in the substrate after annealing at 1000 deg rees C. (C) 1999 American Institute of Physics. [S0021-8979(99)08920-3].