G. N. Mikhailova

Laser solid-phase doping of semiconductors

Abstract Physical processes that occur at nonequilibrium solid-phase diffusion of impurities into semiconductors under CW CO2 laser irradiation are studied. A number of applications of solid-phase processes stimulated by laser radiation are grounded for microelectronics, involving formation of submicron dopant layers, cleaning of dielectric coating on semiconductor wafer surfaces, making of Ohmic contacts, p-n- and heterojunctions.

Calculation of thermal processes upon the laser modification of HTSC ceramics aimed at increasing the critical current

A mathematical model for the heating of a surface layer of HTSC ceramics by a CW laser beam scanned at a constant rate is considered. The calculated depths of the molten region are presented for the heating of the Bi(2223) ceramics by a CW CO2 laser. The theoretical results are in reasonable agreement with the experimental data. The calculations can be used for the optimization of laser processing of superconducting ceramics aimed at increasing the critical current density.

Performance enhancement in high-T c ceramics through melting by Joule heating, infrared lamps, and laser radiation

We have analyzed experimental data on the effect of short-term melting followed by recrystallization on the microstructure and critical current density of YBa2Cu3O7 − x, Bi2Sr2CaCu2O8 − x, and Bi2Sr2Ca2Cu3O10 − x high-Tc ceramics. The ceramics were melted using different heat sources: infrared lamps, laser radiation, and electric current. A significant increase in the critical current density of Bi2Sr2Ca2Cu3O10 − x ceramics (by a factor of 40 at 20 K and by a factor of 8 at 77 K) was achieved using cw CO2 laser irradiation. Melting TiC-doped (0.1%) Bi2Sr2Ca2Cu3O10 − x ceramics with a CO2 laser, followed by annealing, insured an even larger increase in critical current density: by a factor of 35 at 77 K. We have calculated the thickness of the molten layer produced by laser heating of high-Tc ceramics.