Planar n-on-p HgCdTe FPAs for LWIR and VLWIR Applications

Autor: A. Bauer, Johann Ziegler, K.-M. Mahlein, H. Bitterlich, R. Wollrab, Stefan Hanna, T. Schallenberg, H. Lutz, M. Bruder
Rok vydání: 2011
Předmět:
Zdroj: Journal of Electronic Materials. 40:1618-1623
ISSN: 1543-186X
0361-5235
DOI: 10.1007/s11664-011-1659-0
Popis: Mainly driven by space applications, mercury cadmium telluride (MCT) focal-plane arrays (FPAs) have been successfully developed for very long wavelengths (λCO > 14 μm at 55 K). For this purpose, the standard n-on-p technology based on MCT grown by liquid-phase epitaxy (LPE) and involving vacancy doping has been modified to extrinsic doping by a monovalent acceptor. Due to the planar diode geometry obtained by ion implantation, most of the carrier generation volume is located in the p-type region with a thickness of approximately 8 μm. According to our understanding, the Shockley–Read centers connected with the Hg vacancies are thus significantly reduced. This situation should lead to longer minority-carrier lifetimes and smaller generation rates under equilibrium conditions, therefore yielding lower dark current. We indeed observe a reduction by a factor of approximately 15 by using extrinsic doping. Recent dark current data obtained in the temperature range from 55 K to 85 K on 288 × 384 FPAs with λCO(60 K) = 12 μm, either intrinsically or extrinsically doped, corroborate this finding. These data, new results on a 112 × 112 pixel demonstrator array with λCO(55 K) = 14.4 μm, and earlier measurements are compared with Tennant’s Rule 07 established for p-on-n technology.
Databáze: OpenAIRE
Externí odkaz: