H. Lemke

DLTS analysis of nickel-hydrogen complex defects in silicon

Abstract The results of a deep level transient spectroscopy (DLTS) study of nickel–hydrogen complexes in n- and p-type silicon are presented. Hydrogen is incorporated by wet-chemical etching. After etching, eleven electrically active Ni–H related levels are observed. Heat treatment enables us to investigate the thermal stability of Ni–H complexes. Possible structures of the Ni–H defects are proposed.

Hydrogen-induced defects in cobalt-doped n-type silicon

Five new cobalt - hydrogen-related deep levels in cobalt-doped float-zone n-type silicon are identified. The levels are formed after wet chemical etching, polishing or remote plasma hydrogenation. We correlate the levels with the injection of hydrogen into cobalt-doped silicon by deep-level transient spectroscopy (DLTS) depth profiling and capacitance - voltage analysis. Cleaving the sample, without any wet chemical treatment, gives only one DLTS level, the well known Co acceptor at eV. The hydrogen - cobalt complexes show different thermal stabilities. One is stable up to 470 K, but all other defects anneal out at 400 K and lead to an increase of the cobalt acceptor concentration.

Hydrogen - cobalt complexes in p-type silicon

We report on three cobalt - hydrogen related deep levels H(50): eV, H(90): eV and H(150): eV. The levels are formed by wet chemical etching or remote hydrogen plasma treatment and successive annealing at 400 K in cobalt-doped float-zone p-type silicon. The level H(150) is bistable and exhibits a fully reversible transition between an electrically active and an electrically neutral configuration after zero-bias or reverse-bias annealing at temperatures between 310 K and 400 K. We tentatively assign H(90) and H(150) to a CoH complex and H(50) to a complex.

Trivalent behavior of palladium in silicon

Palladium is known to exhibit an acceptor state at EC−0.22 eV in n-type Si and a donor state at EV+0.31 eV in p-type Si. We have identified a third level at EV+(0.140±0.005) eV and attribute it to the double donor state of substitutional Pd. The Pd level positions are very similar to the corresponding levels for Pt. The double donor states of both metals show an electric field dependence of the emission rates and a thermal activation of the hole capture cross sections.

New interpretation of the dominant recombination center in platinum doped silicon

The midgap level in platinum doped n-type silicon, which was proposed to be the dominant recombination center, is identified as a platinum-hydrogen complex. Hydrogenation of the samples is achieved by wet-chemical etching at room temperature. Defect profiles, determined by deep level transient spectroscopy, clearly associate the level with the concentration profile of atomic hydrogen.

Hydrogen–rhodium complexes in silicon

Abstract New hydrogen-induced deep levels in rhodium-doped n- and p-type silicon were observed after hydrogenation by wet-chemical etching. The levels were studied by DLTS measurements on Schottky diodes. We have found in n-type samples the levels E(150) at EC −0.33 eV; E(90) at EC −0.16 eV; and E(70) at EC −0.14 eV. Levels E(150) and E(270) belong to the substitutional rhodium donor and acceptor. Evidence is presented that the level E(70), which was formerly ascribed to isolated rhodium, is due to a hydrogen–rhodium complex. In p-type samples two levels were detected: H(280) at EV +0.50 eV and H(200) at EV +0.37 eV. Two different hydrogen–rhodium complexes are assigned to these levels. The thermal stability of the levels was investigated up to temperatures of 600 K.