30 September 2003 Peculiarities of diffusion p-n junction formation in CdxHd1-xTe graded-bandgap epitaxial structures
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Abstract
Investigations of graded-band-gap photosensitive epitaxial structures based on CdxHg1-xTe of n-type doped by As have been carried out. The epitaxial layers of CdxHg1-xTe(x=0.19÷0.34) grown by evaporation - condensation - diffusion in isothermal conditions (ISOVPE) and CdxHg1-xTe monocrystals (x=0.2;0.3) were used a basic material. As ion implanted (E=100 keV; D=5•1014, 5•1015, 6•1015 cm-2) surface of the epitaxial CdxHg1-xTe layer or highly doped (NAs≈1018 cm-3) thin (d=2÷4 μm surface films obtained by RF sputtering in Hg glow discharge on the monocrystal CdxHg1-xTe whose composition slightly differed from the basic one were used as admixtures. The diffusion of impurity and its activation have been performed in Hg and Te vapour at T > 400°C. Immediately after the diffusion process the samples were exposed to the long-term low-temperature annealing in a flow of Hg saturated vapor for recovery of the initial state of a basic material with respect to native defects. The diffusion profiles of the As distribution were determined by the SIMS analysis. Measurements of the diode structure parameters were carried out by differential Hall effect and conductivity in magnetic fields B=0÷1.8 T1, differential thermo-emf as well as by the direct observation of the p-n transition by EBIC method at 77K. The obtained results exhibit a high electroactivity of As in the samples. A rather complicated shape of the impurity distribution in the ISOVPE epitaxial CdxHg1-xTe points to the multicomponent mechanism of the As diffusion. Spectral and current-voltage characteristics of the graded-band-gap structures, as well as the influence of internal electric field on the structure properties have been investigated. It has been proposed the various ways for improvement of the epitaxial graded-band-gap CdxHg1-xTe structures parameters.
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A. P. Vlasov, A. P. Vlasov, V. K. Pysarevsky, V. K. Pysarevsky, A. V. Shevchenko, A. V. Shevchenko, A. Yu. Bonchyk, A. Yu. Bonchyk, A. Barcz, A. Barcz, } "Peculiarities of diffusion p-n junction formation in CdxHd1-xTe graded-bandgap epitaxial structures", Proc. SPIE 5126, 17th International Conference on Photoelectronics and Night Vision Devices, (30 September 2003); doi: 10.1117/12.517365; https://doi.org/10.1117/12.517365
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