A vertical thin film transistor (TFT) structure allows for a channel
length to be scaled down, below that allowed by lateral TFT structures,
to nanoscale (i.e., below 100 nm). However, while reducing the channel
length, short-channel effects have been found in previous VTFT
structures. Aspects of the new vertical TFT structure allow for the
suppression of some of the short-channel effects. Advantageously, the
capability of defining nanoscale channel length with short-channel effect
suppression allows for p-channel vertical TFTs, where previously these
were impractical. Furthermore, in aspects of the vertical TFT structure,
the gate electrode is entirely vertical and by eliminating the horizontal
overlap of the gate electrode over the drain electrode that present in
earlier vertical TFT structures, parasitic gate-to-drain capacitance is
eliminated. The vertical TFT structure provides size advantages over
lateral TFTs and, furthermore, allows a TFT to be built at the
intersection of electrode lines in an active-matrix configuration.