ZnOThinFilmTransistor RingOscillators withsub75nsecPropagation Delay

useA1203, alsodeposited byAPCVD,asthegate dielectric andAlsource anddrain contacts. We havefabricated simple circuits, including ring oscillators, usingZnO thinfilmsdeposited bylow temperature (200°C)atmospheric pressure chemical Device Fabrication vapordeposition. BottomgateTFTswithaluminum source anddrain contacts typically hadfield effect Bottom-gate ZnO TFTsfabricated onglass substrates mobility >15cm2/Vs.Sevenstageringoscillatorswereusedinthis work.First, 100nm thick Crwasionoperated atfrequency ashighas1MHz forasupply beamsputtered ontoclean glass substrates andpatterned voltage of32V,corresponding toapropagation delay byphotolithography andwetetching toformgate lessthan75 nsec/stage. Thesecircuits alsohad electrodes. Next, a 100nm thickA1203 layer was propagation delay less than150ns/stage atasupply deposited ontotheCrgates byAPCVD at200°Cfrom voltage of18V. To ourknowledge, these arethe trimethylaluminum