Poly-Si stripe TFTs by grain-boundary controlled crystallization of amorphous-Si

Abstract

In this work, we fabricated high-performance P- and N-channel poly-Si TFTs with 16-nm gate dielectric (ALD Al2O3) at temperatures not exceeding 550degC. Using preformed a-Si lines, the grain boundaries formed during laser crystallization were predominantly location-controlled. A diode-pumped Yb:YAG thin disk green laser was used for crystallization and dopant activation. The film crystallinity was characterized with electron backscatter diffraction (EBSD). The sheet resistance of the crystallized films was studied as a function of the laser treatment energy, the location, and the orientation. The realized TFTs exhibited a field-effect mobility of 51.5 cm2/Vs and 61.9 cm2/Vs, and a subthreshold swing of 0.14 and 0.16 V/decade for p- and n-channel devices, respectively.