Stability of continuous-wave laser-crystallized epilike silicon transistors

Abstract

Stability of high-hole-mobility thin-film transistors (TFTs) on single-grainlike silicon channels formed by continuous-wave laser crystallization during hot-carrier stressing (HCS) was studied. As channel layers become thicker, laser-mediated channel crystallinity increases, increasing channel roughness. On such epilike polycrystalline silicon substrates, the poorer interface quality for thicker channels, even those with lower tail-state densities of grain traps, is responsible for the extensive charge trapping and creation of deep-state densities in the fabricated TFTs due to HCS. Hence, on a thin channel with a thickness of 50 nm and ultrasmooth surfaces, HCS hardly degrades the electrical parameters of the devices. (c) 2007 American Institute of Physics.