Abstract

The absorption of CO₂ laser light in silicon is dominated by free-carrier transitions; therefore, the penetration depth of the light depends on the carrier density. This extrinsic absorption mechanism can be controlled by varying the carrier density through doping or ion-implanting samples. Control of the absorption coefficient is especially important in applications where one would like to achieve a deeper penetration of the laser light than is achievable with a laser for which the absorption is dominated by intrinsic interband transitions. Furthermore₅ one can use a CO₂ laser to preferentially deposit energy in heavily-doped layers which are encapsulated by lightly-doped layers of the material. We have studied pulsed CO₂ laser annealing of boron-_, arsenic-_, and antimony-implanted silicon.

© 1984 Optical Society of America