Growth of high quality epitaxial CdxHg1-xTe films by sputter deposition

Abstract Epitaxial Cd x Hg 1- x Te films have been simultaneously grown onto several CdTe substrates (total area 20 cm 2 ) by cathodic sputtering in a mercury vapour plasma. The layers are grown on substrates heated up to 310°C with a deposition rate of 0.6μ/hour (total thickness ⩽ 30 μm). Crystallographic characterization has been carried out using different techniques such as: reflection X-ray topography, the measurement of the FWHM of the diffraction profile, transmission electron microscopy (TEM) and Rutherford back scattering (RBS). TEM, rocking curves and RBS results reveal a high crystallographic quality (dislocation density in the layer is approximately 10 4 cm -2 ). The Hall coefficient of Cd x Hg 1- x Te epitaxial layers has been measured between 4 and 300 K. At 77 the results concerning layers deposited at 285°C (Cd composition of 0.23 and thickness of 16μm) are about n = 2.7 × 10 16 cm -3 with a Hall mobility of 64000 cm 2 V -1 s -1 and for a Cd composition of 0.31 (thickness of 18 μm) we obtained n =1.6×10 16 cm -3 and a Hall mobility of 16000 cm 2 V -1 s -1 . The film properties were improved by post deposition annealing in a Hg atmosphere using a two-zone furnace. An increase in electron mobility of n type films to values of those for bulk material were obtained using unoptimized annealing parameters.