Abstract

We report on the latest development in the integration of thin film silicon with PLZT for smart spatial light modulators (S-SLMs). PLZT is an electrooptic (EO) material that satisfies most of the requirements for a S-SLM. It exhibits a large quadratic EO effect requiring relatively small modulation voltages. Also modulation speeds as high as 180 MHz has been demonstrated in our laboratories. One way of integrating this material with silicon technology is to deposit polysilicon on PLZT wafers and then recrystallize silicon for subsequent device fabrication using a scanning laser beam. The major problem was the high leakage current of fabricated transistors due to grain boundaries and crystal imperfection after the laser recrystallization process. As a result of these defects, the transistor yield was limited to 20-30%, preventing us from fabricating large arrays. We have now developed our process to the point where the yield has become 85%. Based on these improvements, 8×8 XOR and 1-bit memory cells with up to ten transistors per unit cell have been fabricated.

© 1991 Optical Society of America