Laser Damage in Semiconductors.
Abstract
Experimental damage thresholds for Si, Ge, GaAs, GaAs(x)P(1-x) and GaP have been determined at 10.6 x 10 to the -6 and 1.06 x 10 to the -6 laser wavelengths. For CW CO(2) laser damage, all the thresholds are of the order of a few kW/cm(2) for an irradiation time of about 0.10 second. At 1.06 x 10 to the -6 wavelength and for nanosecond pulses, the damage thresholds are of the order of 10(9) W/cm(2). The damage thresholds can be explained by assuming that the anomalous absorption takes place through the parametric instability of the type formulated by DuBois and Goldman. The plasma concentration required for the onset of this instability at 10.6 x 10 to the -6 is easily achieved by photon induced excitation of the valence electrons to the conduction band through a continuous distribution of Shockley surface states. At 1.06 x 10 to the -6, the required plasma concentration in case of Germanium and Silicon is produced by band to band transitions and by Zener tunneling in case of GaAs, GaAs(x)P(1-x) and GaP. In practice the damage occurs both at the surface of the semiconductor and within the bulk, creating defects that cause carrier REMOVAL AND MOBILITY DEGRADATION. The defects so created are more active at lower temperatures than at room temperature as seen from the experimentally measured Hall mobility versus temperature curves before and after laser damage. Carrier removal and mobility degradation curves appear qualitatively to be similar to those observed for electron, neutron and r-ray damage.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1977
- Accession Number
- ADA039135
Entities
People
- S. K. Gulati
- Wayne W. Grannemann
Organizations
- University of New Mexico