Capacitance–voltage modeling of mid-wavelength infrared nBn detectors
Abstract
Capacitance–voltage measurements are a powerful technique to determine doping profiles of semiconductor pn junctions and Schottky barrier diodes. The measurements were recently extended to III-V-based mid-wavelength nBn infrared detectors, and absorber doping densities have been extracted using the widely accepted Schottky approximation, where the potential drop across the device is assumed to be across the depleting absorber layer. However, this approach is limited to when the absorber region of the nBn is under high reverse bias and thus is only able to extract the absorber region doping profile. Here, we introduce a semi-analytical model that is capable of extracting barrier dopant polarity, doping concentration, and thickness, as well as contact and absorber layer doping concentrations, all from a capacitance–voltage measurement. Rather than solely considering the potential drop across the depleting layers, it considers the potential drop across the accumulating layer as well. This negative charge accumulation occurs for the contact and absorber layers in the case of reverse and forward biases, respectively. This allows for a single model to be applied to a capacitance–voltage curve at forward and reverse biases and it can provide regions of bias where the absorber transitions from depletion to accumulation. We compare the agreement of the semianalytical model with modeling results from commercially available finite element method software and experimental capacitance–voltage data. Finally, we show that the method is consistent with the Schottky approximation of extracting absorber doping densities at high reverse bias and discuss the model's limitations.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Mar 09, 2023
- Source ID
- 10.1063/5.0138468
Entities
People
- A. T. Newell
- Benjamin Pinkie
- Christian Morath
- Gamini Ariyawansa
- Joshua M. Duran
- Julie V. Logan
- Preston T. Webster
- Rigo A. Carrasco
- Zinah M. Alsaad
Organizations
- Air Force Research Laboratory
- National Research Council
- University of New Mexico