Silicon damage caused by CCl4 reactive ion etching: Its characterization and removal by rapid thermal annealing

Abstract
It is demonstrated that CCl4 reactive ion etching produces lattice damage, chlorine contamination, and modified electrical properties at etched silicon surfaces. The structural and electrical property changes caused by the chemical-physical etching of CCl4 reactive ion etching are found to be similar to the structural and electrical property changes caused by the physical etching of inert gas ion beam etching. Rapid thermal anneals of 1100 °C for 10 sec are shown to give both structural recovery and electrical property recovery to CCl4-etched silicon surfaces. The chlorine contamination is also shown to be driven off by this rapid thermal anneal. Although it has been reported that rapid thermal annealing does not restore reactive ion-etched silicon surfaces in the case of certain other etching gases, it is effective here in a case where no substantial residue layer is present after etching and impurities present after etching evolve out during the rapid heat pulse.