Sol-gel processed SnO2 thin-film transistors (TFTs) were fabricated on SiO2/p+ Si substrates. The SnO2 active channel layer was deposited by the sol-gel spin coating method. Precursor concentration influenced the film thickness and surface roughness. As the concentration of the precursor was increased, the deposited films were thicker and smoother. The device performance was influenced by the thickness and roughness of the SnO2 active channel layer. Decreased precursor concentration resulted in a fabricated device with lower field-effect mobility, larger subthreshold swing (SS), and increased threshold voltage (Vth), originating from the lower free carrier concentration and increase in trap sites. The fabricated SnO2 TFTs, with an optimized 0.030 M precursor, had a field-effect mobility of 9.38 cm2/Vs, an SS of 1.99, an Ion/Ioff value of ~4.0 × 107, and showed enhancement mode operation and positive Vth, equal to 9.83 V.
The hydrogenation effect was studied in the fabrication of amorphous silicon thin film transistor using APCVD technique. The inverse staggered type a-Si TFTs were fabricated with the deposited a-Si and SiO2 films by the atmospheric pressure (AP) CVD. The field effect mobility of the fabricated a-Si TFT is 0.79 cm2/Vs and threshold voltage is 5.4V after post hydrogenation. These results can be applied to make low cost a-Si TFT array using an in-line APCVD system.
A fully transparent conformal organic thin-film field-effect transistor array is obtained based on an ultrathin embedded metal-grid electrode and a solution-processed C8-BTBT film.
Influence of Active Channel Layer Thickness on SnO2 Thin-Film Transistor Performance