Chemical Etching of CdTe in Aqueous Solutions of H2O2-HI-Citric Acid

Abstract

An iodine-based etching system, H 2 O 2 -HI-citric acid, has been developed and tested on CdTe samples with orientations (111)A, (111)B, (110), and (100). The etching velocity of CdTe was shown to depend on sample orientation and other etching conditions. The surface roughness was comparable with that of the surfaces after Br-methanol treatment. A comparative study of the chemical composition of the (211)B CdZnTe surfaces etched under different conditions was performed. X-ray photoelectron spectroscopy (XPS) measurements showed that all treated surfaces of CdZnTe samples are enriched with Te. The HI-based treatment seems to be more acceptable than the Br-methanol treatment in terms of elimination of Te oxides from the surface, however.

Chemical Interaction of CdTe and CdZnTe with Aqueous Solutions of H2O2-HI-Tartaric Acid

“…The XPS spectra in the Cd3d region also indicates a doublet structure corresponding to the Cd metallic state. Table IV summarizes 6 Despite this, the HI-based treatment appears to be more acceptable with regard to elimination of Te oxides from the surface. We have found oxygen and carbon as contaminants in the surface layer as results of sample exposure to air or impact of isopropyl alcohol used as a storage solution.…”

“…The XPS spectra were first measured on as-received surfaces and then after annealing treatment in UHV conditions. The procedure, which has been applied earlier, 6 consisted of several steps. The samples were first loaded at 100°C and held for 20 min.…”

“…According to our previous investigation, solutions of the H 2 O 2 -HI system are promising and could be used as a basis for developing a wide range of etchants for the chemical treatment of CdTe. 6 Introduction of aqueous solutions of some organic acids to the etching composition also promotes their viscosity increase. Therefore, it is possible to obtain etchants with low etching rates, which allows us to improve the quality of surface etching.…”

X-ray photoemission analysis of chemically treated GaTe semiconductor surfaces for radiation detector applications

“…Similar surface treatments related to II-VI binary and I-III-VI ternary semiconductor devices have been explored only recently. [4][5][6][7][8][9][10] In this work, various wet chemical treatments with H 3 PO 4 :H 2 O 2 :H 2 O, H 3 PO 4 :H 2 O, and H 2 O 2 :H 2 O were accessed. The chemical processing of the GaTe surface is examined in detail by interrupting the treatment cycle and characterizing with monochromatic x-ray photoelectron spectroscopy ͑XPS͒ to examine the surface reactions associated with each separate chemical treatment.…”

Passivation of Semiconductor Surfaces for Improved Radiation Detectors: X-Ray Photoemission Analysis

“…This treatment removes the native oxide but leaves a Te-rich surface resulting in metal/CZT interface degradation and excessive leakage currents. [1][2][3] Alternative surface preparation methods have been proposed for surface passivation [3][4][5][6] but have not been fully characterized nor implemented for practical device fabrication.…”