Total ionizing dose effects on digital micromirror devices

Abstract

There is interest in deploying digital micromirror devices (DMDs) in space for use in multi-object spectrometers, but the devices must first be qualified for space deployment. An environmental test campaign has been carried out on eXtended Graphics Array (XGA) DMDs to qualify the devices for space deployment. The campaign has included mechanical shock and vibration, low temperature, proton radiation, and heavy ion radiation testing. XGA DMDs have passed each test at a level suitable for space deployment. Our paper reports on gamma radiation testing of XGA DMDs, the final portion of the environmental test campaign. Gamma radiation causes total ionizing dose (TID). A total of 19 DMDs were irradiated to TIDs between 16 and 45 krad(Si) while biased and 24 and 76 krad(Si) while unbiased. The effects of TID on DMDs are similar to other electrostatically operated micro-electrical mechanical systems, and all irradiated DMDs were fully recovered by annealing. In addition to testing, radiation modeling of the space environment was performed to determine the expected TID for various space mission scenarios. DMDs have minimal susceptibility to TID effects, and the effects do not significantly compromise the use of the devices for space missions in orbit at L2 or low Earth orbit.