Defeating the trade-off between process complexity and electrical performance with vertical zinc oxide transistors

Short-channel devices can show high performance, but typically have difficult processing and alignment steps. We show here a simple low-temperature process to produce sub-micrometer-channel zinc-oxide thin-film transistors. The thickness of the gate metal defines the channel length, while a combination of conformal and non-conformal depositions create the channel and electrodes. Layer-to-layer alignment is noncritical. With mobility values ten times greater than amorphous silicon, high on/off current ratios at low voltage, good yield, and good thermal sinking in operation, these vertical transistors unite the performance of metal oxide semiconductors with the advantages of short-channel devices.