Numerical Modeling of SRH and Tunneling Mechanisms in High-Operating-Temperature MWIR HgCdTe Photodetectors

• Published in: Journal of electronic materials Vol. 44; no. 9; pp. 3056 - 3063
• Main Authors: Vallone, Marco, Mandurrino, Marco, Goano, Michele, Bertazzi, Francesco, Ghione, Giovanni, Schirmacher, Wilhelm, Hanna, Stefan, Figgemeier, Heinrich
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.09.2015; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Electronics and Microelectronics; High temperature; Infrared imaging systems; Instrumentation; Materials Science; Mathematical models; Mercury cadmium telluride; Numerical analysis; Optical and Electronic Materials; Solid State Physics; Infrared photodetectors; impact ionization; HgCdTe; generation–recombination; tunneling; numerical simulation
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-015-3767-8

A combined experimental and numerical simulation study is presented on two sets of nominally identical Hg 1 - x Cd x Te single-color back-illuminated midwave-infrared n -on- p photodetectors grown by liquid-phase epitaxy, p -doped with Hg vacancies and with Au, respectively. The present numerical model includes a novel formulation for band-to-band tunneling, which overcomes the intrinsic limitations of the classical Kane description without introducing numerical issues typical of other approaches. Our study confirms that adopting n -on- p architectures, avoiding metal vacancy doping, and reducing the acceptor density in the absorber region are prerequisites for obtaining high-operating-temperature photodetectors. A significant contribution to the dark current in both sets of devices is attributed to impact ionization, crucial to obtain a satisfactory explanation for the measured characteristics also at low to intermediate bias.