ISSN 1063-7826, Semiconductors, 2007, Vol. 41, No. 3, pp. 341–344. © Pleiades Publishing, Ltd., 2007. Original Russian Text © I.B. Chistokhin, A.K. Gutakovskiœ, A.S. Deryabin, 2007, published in Fizika i Tekhnika Poluprovodnikov, 2007, Vol. 41, No. 3, pp. 352–355.
AMORPHOUS, VITREOUS, POROUS, ORGANIC, AND MICROCRYSTALLINE SEMICONDUCTORS; SEMICONDUCTOR COMPOSITES
Structure and Electrical Properties of Polycrystalline SiGe Films Grown by Molecular Beam Deposition I. B. Chistokhin^, A. K. Gutakovskiœ, and A. S. Deryabin Institute of Semiconductor Physics, Siberian Division, Russian Academy of Sciences, pr. akademika Lavrent’eva 13, Novosibirsk, 630090 Russia ^e-mail:
[email protected] Submitted August 14, 2006; accepted for publication August 28, 2006
Abstract—The structural and electrical properties of polycrystalline Si0.5Ge0.5 films 150 nm thick grown by molecular beam deposition at temperatures of 200–550°C on silicon substrates coated with amorphous layers of silicon oxynitride were studied. It is shown that the films consist of a mixture of amorphous and polycrystalline phases. The amorphous phase fraction decreases from ~50% in films deposited at 200°C to zero in films grown at 550°C. Subsequent 1-h annealing at a temperature of 550°C results in complete solid-phase crystallization of all films. The electron transport of charge carriers in polycrystalline films occurs by the thermally activated mechanism associated with the energy barrier of ~0.2 eV at grain boundaries. Barrier lowering upon additional annealing of SiGe films correlates with an increase in the average grain size. PACS numbers: 61.72.Mm, 72.80.Ng, 73.61.Le DOI: 10.1134/S1063782607030189
1. INTRODUCTION Recently, uncooled microbolometric arrays of the infrared region that are based on thermoresistive properties of a sensitive element thermally insulated from a readout integrated circuit have been actively developed [1]. Materials for fabricating bolometric elements should have a high temperature coefficient of resistance (TCR), low noise and thermal conductivity, and low temperature of layer deposition (