Analysis of Etched CdZnTe Substrates

• Published in: Journal of electronic materials 2016-09, Vol.45 (9), p.4502-4510
• Main Authors: Benson, J. D., Bubulac, L. O., Jaime-Vasquez, M., Lennon, C. M., Arias, J. M., Smith, P. J., Jacobs, R. N., Markunas, J. K., Almeida, L. A., Stoltz, A., Wijewarnasuriya, P. S., Peterson, J., Reddy, M., Jones, K., Johnson, S. M., Lofgreen, D. D.
• Format: Article
• Language: English
• Subjects: Aluminum; Atomic properties; Cadmium zinc tellurides; Characterization and Evaluation of Materials; Chemistry and Materials Science; Contamination; Damage; Electronics and Microelectronics; Etching; Flakes; Grit; Instrumentation; Materials Science; Methanol; Molecular beam epitaxy; Optical and Electronic Materials; Particulates; Polishing; Silicon dioxide; Solid State Physics; State of the art; Substrates; Wafers
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-016-4642-y

State-of-the-art as-received (112)B CdZnTe substrates have been examined for surface impurity contamination and polishing residue. Two 4 cm × 4 cm and one 6 cm × 6 cm (112)B state-of-the-art as-received CdZnTe wafers were analyzed. A maximum surface impurity concentration of Al = 1.7 × 10 15  atoms cm −2 , Si = 3.7 × 10 13  atoms cm −2 , Cl = 3.12 × 10 15  atoms cm −2 , S = 1.7 × 10 14  atoms cm −2 , P = 1.1 × 10 14  atoms cm −2 , Fe = 1.0 × 10 13  atoms cm −2 , Br = 1.2 × 10 14  atoms cm −2 , and Cu = 4 × 10 12  atoms cm −2 was observed on the as-received CdZnTe wafers. CdZnTe particulates and residual SiO 2 polishing grit were observed on the surface of the as-received (112)B CdZnTe substrates. The polishing grit/CdZnTe particulate density on CdZnTe wafers was observed to vary across a 6 cm × 6 cm wafer from ∼4 × 10 7  cm −2 to 2.5 × 10 8  cm −2 . The surface impurity and damage layer of the (112)B CdZnTe wafers dictate that a molecular beam epitaxy (MBE) preparation etch is required. The contamination for one 4 cm × 4 cm and one 6 cm × 6 cm CdZnTe wafer after a standard MBE Br:methanol preparation etch procedure was also analyzed. A maximum surface impurity concentration of Al =  2.4 × 10 15  atoms cm −2 , Si = 4.0 × 10 13  atoms cm −2 , Cl = 7.5 × 10 13  atoms cm −2 , S = 4.4 × 10 13  atoms cm −2 , P = 9.8 × 10 13  atoms cm −2 , Fe = 1.0 × 10 13  atoms cm −2 , Br = 2.9 × 10 14  atoms cm −2 , and Cu = 5.2 × 10 12  atoms cm −2 was observed on the MBE preparation-etched CdZnTe wafers. The MBE preparation-etched surface contamination consists of Cd(Zn)Te particles/flakes. No residual SiO 2 polishing grit was observed on the (112)B surface.