Ion etching of HgCdTe: Properties, patterns and use as a method for defect studies

Analysis is performed of the contemporary views on the effect of ion etching (ion-beam milling and reactive ion etching) on physical properties of HgCdTe and on the mechanisms of the processes responsible for modification of these properties under the etching. Possibilities are discussed that ion etching opens for defect studies in HgCdTe, including detecting electrically neutral tellurium nanocomplexes, determining background donor concentration in the material of various origins, and understanding the mechanism of arsenic incorporation in molecular-beam epitaxy-grown films

Ion etching of HgCdTe: Properties, patterns and use as a method for defect studies

Analysis is performed of the contemporary views on the effect of ion etching (ion-beam milling and reactive ion etching) on physical properties of HgCdTe and on the mechanisms of the processes responsible for modification of these properties under the etching. Possibilities are discussed that ion etching opens for defect studies in HgCdTe, including detecting electrically neutral tellurium nanocomplexes, determining background donor concentration in the material of various origins, and understanding the mechanism of arsenic incorporation in molecular-beam epitaxy-grown films

Background donor concentration in HgCdTe

Studies of background donor concentration (BDC) in HgCdTe samples grown with different types of technology were performed with the use of ion milling as a means of eliminating the compensating acceptors. In bulk crystals, films grown with liquid phase epitaxy and films fabricated with molecular beam epitaxy (MBE) on Si substrates, BDC of the order of ~1014 cm-3 was revealed. Films grown with metal−organic chemical vapour deposition and with MBE on GaAs substrates showed BDC of the order of ~1015 cm-3. A possibility of assessing the BDC in acceptor (arsenic)−doped HgCdTe was demonstrated. In general, the studies showed the effectiveness of ion milling as a method of reducing electrical compensation in n−type MCT and as an excellent tool for assisting evaluation of BDC

Optical and electrical studies of arsenic-implanted HgCdTe films grown with molecular beam epitaxy on GaAs and Si substrates

A defect study was performed on arsenic-implanted Hg1-xCdxTe (x = 0.23–0.30) films with graded-gap surface layers, grown with molecular-beam epitaxy on GaAs and Si substrates and designed for fabrication of ‘p+–n’-type photodiodes. First, formation of n+–p structure was investigated in p-type material, in order to study radiation-induced donor defects. Next, formation of p+–n structure was investigated in the course of implantation in n-type material and arsenic activation annealing. Influence of the graded-gap surface layer was found to be expressed in the degree of saturation of the concentration of radiation-induced defects, with results obtained on arsenic- and boron-implanted material differing due to the difference in the ion masses

Optical and electrical studies of arsenic-implanted HgCdTe films grown with molecular beam epitaxy on GaAs and Si substrates

A defect study was performed on arsenic-implanted Hg1-xCdxTe (x = 0.23–0.30) films with graded-gap surface layers, grown with molecular-beam epitaxy on GaAs and Si substrates and designed for fabrication of ‘p+–n’-type photodiodes. First, formation of n+–p structure was investigated in p-type material, in order to study radiation-induced donor defects. Next, formation of p+–n structure was investigated in the course of implantation in n-type material and arsenic activation annealing. Influence of the graded-gap surface layer was found to be expressed in the degree of saturation of the concentration of radiation-induced defects, with results obtained on arsenic- and boron-implanted material differing due to the difference in the ion masses