ZnO TFT Circuits

I demonstrated several ZnO TFT circuits for the first time. Several circuit blocks are important in a hybrid system architecture, notably oscillators, scanning circuits, low-noise amplifiers, and rectifiers. I worked on the circuits below; amplifiers and rectifiers (based on ZnO diodes) have also been demonstrated by junior students I taught.

Cross-coupled LC oscillator: resonant circuit allows high frequency oscillations > TFT fT; TFT parasitic capacitances resonate with LAE-enabled high-Q inductors so long as the condition for positive feedback is met. Max oscillation frequency = 35MHz.

Colpitts LC oscillator: a different resonant topology that can overcome some of the challenges of the cross-coupled oscillator because (1) the Miller effect seen in the cross-coupled topology is eliminated; and (2) only one stage consuming bias current is required. However, in implementation, an advantage over the CC topology was not observed because of the more stringent oscillation condition.

Scanning circuit: scanning circuits allow access to a large number of sensors in a LAE system while reducing the number of interconnects between the LAE domain the CMOS IC.