Charge collection scanning transmission electron microscopy for advanced infrared semiconductor devices

Techniques for the reduction of growth-induced crystal defects are of critical importance to the efforts geared toward development of thin-film heteroepitaxial materials and devices for infrared sensor applications based on large-area semiconductor substrates. These defects, such as threading and misfit dislocations, commonly occurring during growth and processing of the respective heteroepitaxial material systems, can adversely impact the performance and reliability of the fabricated infrared focal plane array (IRFPA) devices, particularly those for long-wave infrared (LWIR) detection. This impact will be most severe if these defects are situated in the infrared device active region and so can interfere with its electrical functionality. Aimed toward reduction and mitigation of the above crystal defects, this Phase I proposal presents a systematic approach for their characterization and analysis using electron beam-induced current (EBIC) in a scanning transmission electron microscope (STEM). In this proposal, special emphasis is placed on the expected key challenges of meeting optimal specimen preparation requirements as well as overcoming the intrinsic and inherent charge collection issue, such as dark current noise, specific to the respective material systems.