High Stability, Low Leakage Nanocrystalline Silicon Bottom Gate Thin Film Transistors for AMOLED Displays

We report performance characteristics of nanocrystalline silicon thin-film transistors (TFTs) fabricated at 280 °C by plasma-enhanced chemical vapor deposition. The TFTs exhibit field-effect mobility of 0.8 cm
²
V
^-1
s
^-1
, threshold voltage of 4 V, on/off current ratio about 10
⁸
with an off-current of 10
^-13
A, and subthreshold slope of 0.8 V/dec. Bias stress measurements show that the TFT is 3-5 times more stable than the hydrogenated amorphous silicon (a-Si:H) counterpart, with a shift in threshold voltage that is less than 5 % at a gate voltage of 15 V.