Electronic and isochronal annealing properties of electron traps in rapid thermally annealed SiO2-capped n-type GaAs epitaxial layers

We have recently shown [P. N. K. Deenapanray , Appl. Phys. Lett. 77, 626 (2 000)] that four electron traps S1(E-c-0.23 eV), S2(E-c-0.46 eV), S3(E-c-0.7 2 eV), and S4(E-c-0.74 eV) are introduced in rapid thermally-annealed (RTA) SiO2-capped n-type GaAs epitaxial layers. In the present study, we have us ed deep level transient spectroscopy to investigate the electronic and anne aling properties of these deep levels. The electron emission kinetics of S1 is enhanced by an electric field, and the activation energy of S1 decrease s linearly from similar to 233 to similar to 199 meV when the field is incr eased from 7.5x10(4) to 13.4x10(4) V cm(-1). The intensities of S1, S2, and S4 show Arrhenius-like dependencies on the RTA temperature, which relate t o the outdiffusion of Ga atoms into the SiO2 layer. The intensity of S2(V-G a-Si-Ga) also increases exponentially with the square of the annealing time for RTA at 800 degrees C. Isochronal annealing experiments show that S1 an d S2 are thermally stable below 500 and 400 degrees C, respectively. S4, wh ich is a member of the EL2 family, is stable up to 600 degrees C. Secondary defects are introduced during isochronal annealing above 400 degrees C, an d some of these defects are thermally stable at 600 degrees C. (C) 2000 Ame rican Institute of Physics. [S0021-8979(00)02622-0].