Tri-Gate Polycrystalline Silicon Thin-Film Transistors Fabricated by Continuous-Wave Laser Lateral Crystallization with Improved Electron Transport Properties

摘要

Tri-gate channel structures were applied to polycrystalline silicon (poly-Si) thin-film transistors (TFTs) fabricated by continuous-wave (CW) laser lateral crystallization (CLC), We had two objectives in using tri-gate structures in CLC poly-Si TFTs. One was the enhancement of effective electron mobility (μ_(eff)) by using the tensile strain induced by the CLC process and the lateral-strain-relaxation effect in tri-gate structures. The other was the reduction of μ_(eff) variation caused by increasing the number of surfaces with different crystal orientations by up to a factor of three. By applying tri-gate structures to CLC poly-Si TFTs, both 8% μ_(eff) enhancement and 41% reduction of μ_(eff) variation were achieved at the surface carrier density of 5 x 10~(12) cm~(-2). These results are expected to be useful for the device size shrinkage of high-performance poly-Si TFT circuits.