Methodologies for Developing Extremely Large IR Scene Projectors

We have previously demonstrated mid-IR (lambda = 3.6 & #956;m) 512 x 512 LED arrays for infrared scene projection (IRSP). With this Phase I effort we will be laying the ground work for moving these arrays (in Phase II) to 1024 x 1024 and then 2048 x 2048 pixels. The Phase I effort will entail the evaluation, characterization, and comparison of commercially available three and four inch GaSb substrates with the two inch substrates that we are familiar with. We will then (also in Phase I) grow LED test structures on all of the wafers, characterize the LEDs, and compare the results. A 1024 x 1024 LED array with 48 & #956;m pixel pitch will fit on a 3 inch wafer, but it will be tight. In Phase I we propose evaluating the uniformity of the epitaxial layer close to the wafer"s edge. If both Phase I experiments are successful, we will be ready to fabricate 1024 x 1024 IRSP LED arrays early in the Phase II effort, with a move to 2048 x 2048 achieved later in Phase II as a result of a pixel shrink.