A Behavioral Model for High Ge Content in Si/Si1−xGex Multi-Quantum Well Detector

This paper presents a behavioral model for a Si/Si
_1−x
Ge
_x
multi-quantum well (MQW) detector that predicts device characteristics to investigate the effect of increasing Ge content in Si/Si
_1−x
Ge
_x
MQW. The modeling approach in this paper is based on a physical instead of empirical approach, which allows to obtain a predictive behavioral analysis of high Ge content with only a few fitting parameters. The model is used to simulate device transfer characteristics with respect to various amounts of Ge content used for Si
_1−x
Ge
_x
layer in MQW. The simulation results of the proposed model are validated with the experimental data. The simulated and the experimental data are consistent over a wide range of Ge content varied from 30% up to 50%. The primary objective of this paper is to optimize Ge content in the Si/Si
_1−x
Ge
_x
MQW detector to achieve desired thermal sensitivity measured in terms of temperature coefficient of resistance for a potential microbolometer application. This is the first study in the literature to develop such a highly predictive behavioral model of a Ge-enriched Si/Si
_1−x
Ge
_x
MQW. The study also presents the effect of including the carbon delta layers at the Si/Si
_1−x
Ge
_x
heterointerface on the device transfer characteristics. The effect of Ge content on the overall noise is also investigated by the noise characterization of the test devices.