Studying C-V Characteristics of MIS Structures with PE-ALD Al2O3 on HgCdTe Oxidized in Remote RF-Plasma

• Main Authors: Zakirov, Evgeny R., Kesler, Valeriy G., Sidorov, Georgiy Yu
• Format: Conference Proceeding
• Language: English
• Subjects: Al 2 O 3; atomic layer deposition; capacitance-voltage; Conductivity; HgCdTe; II-VI semiconductor materials; Insulators; LWIR; MIS; native oxide; Oxidation; Photodiodes; Plasmas; remote plasma; surface passivation; Surface resistance
• ISSN: 2473-8573
• DOI: 10.1109/APEIE59731.2023.10347577

Metal-insulator-semiconductor (MIS) structures have been made on narrowband n- and p-Hg 1−x Cd x Te(x ≈ 0.22) preliminary chemically cleaned and then oxidized in remote oxygen plasma. Plasma was supplied by an RF generator within a commercial system for plasma-enhanced atomic layer deposition (PE-ALD). An Al 2 O 3 insulating film was deposited on prepared HgCdTe in this system without exposing samples to the ambient atmosphere. HgCdTe epitaxial films comprising or not a surface graded-gap layer (SGGL) have been examined, to reveal its contribution to the electrical properties of the structures. Obtained MIS C-V characteristics reveal near-ideal low-frequency behavior with weak stretching and a narrow hysteresis loop due to low densities of fast and slow surface states. The effective insulator fixed charge has a negative sign with a density of ~1∙10 12 cm −2 . There is no "p-to-n" conductivity type conversion in the structures on HgCdTe grown without the SGGL. The obtained results can be useful for development of HgCdTe-based devices. The proposed passivation approach is compatible with a technology of HgCdTe focal plane arrays (FPAs) manufacturing.