Abstract
Deep level defects produced by quenching from 1175 degrees C silicon doped with Au, Ag, Fe, Cu or Ni have been observed using transient capacitance spectroscopy. In both Au- and Ag-doped samples a hole trap at Ev+0.48 eV was observed, with an electron trap at Ec-0.28 eV present in the Au-doped material. In quenched, Fe-doped samples three hole traps were observed (Ev+0.32 eV, Ev+0.39 eV, Ev+0.40 eV), in agreement with previous measurements. In both Cu- and Ni-doped samples, one hole trap was observed (Ev+0.53 eV for Cu, Ev+0.33 eV for Ni), which was also seen in the as-diffused material. Undoped samples displayed a quenched-in, hole trapping defect at Ev+0.43 eV. All defect states, with the exception of the Ev+0.40 eV Fe-interstitial centre, were neutralised to a depth of about 7 mu m by a 2 h exposure at 200 degrees C to a low-pressure hydrogen plasma. Results are also given for the motion of the Ev+0.40 eV Fe-related centre and the Ec-0.28 eV Au-related centre under the action of the electric field in reverse-biased junction diodes. Using a simplified treatment mobilities at 25 degrees C of 9*10-15 cm2V-1s-1 for the Ev+0.40 eV state, and 2*10-15 cm2V-1s-1 for the Ec-0.28 eV state were estimated.