Molecular Dynamics Growth Model for MBE HgCdTe

The highest performing infrared (IR) detectors are fabricated from alloys of HgCdTe (MCT) grown by molecular beam epitaxy (MBE) on lattice-matched substrates. Although the best performing IR detectors, MCT-based imaging arrays exhibit higher than anticipated noise, especially random telegraph noise (RTN) that occurs in seemingly random sets of pixels.  It is presently believed that RTN originates from extended defects, such as dislocations and impurity clusters, which themselves originate from strain in the crystal.  Despite the use of lattice-matched substrates, small amounts of strain can form within the multiple, slightly mismatched epitaxial layers deposited to form complex device structures.  We propose to develop a molecular dynamics simulation-based MBE growth model for MCT that will allow optimization of the device structure and MBE process parameters to minimize the occurrence of extended defects and RTN. In Phase I, SW parameters were developed and MBE growth simulations showed the formation of extended defects. In Phase II, the model will be refined, and device structures and growth parameters will be adjusted at an established MCT foundry based on guidance from the model.