MOSFET's fabricated in laser-recrystallized Silicon on Quartz using selectively absorbing dielectrical layers

MOSFET's were fabricated in laser-recrystallized silicon islands on fused quartz substrates using a standard n-channel self-registered poly-gate process. Selective absorption obtained with patterned dielectric films was used to control the shape of the melt front during recrystallization of patterned LPCVD polysilicon islands. IR imaging of the laser-heated region was used to optimize and monitor the melt front shape. Devices with various channel lengths and widths were fabricated and the dependence of threshold voltage, channel mobility, and subthreshold leakage on recrystallization conditions and device dimensions were studied. Devices with and without back-channel implants were compared on the same wafer and for the same laser annealing conditions. The back-channel implant consistently reduced the subthreshold leakage to less than 1 pA/µm.