Simulation and experiments towards ferroelectric-gate field effect transistors

The memory functionality can be retained even after the power is turned off and the readout properties are not destructive for ferroelectric gate heterojunction field effect transistors (HFETs).This project is to simulate AlGaN/GaN HFETs and ferroelectric gate HFETs using Silvaco/Atlas software, and also develop sol-gel based ferroelectric thin-film deposition method. The simulation results of the HFET devices were compared with experimental data reported in the literature, confirming the suitability of the simulation method. Lead Zirconium Titanate (PZT) is chosen as the ferroelectric material. PZT thin films were prepared by sol-gel method using zirconium(IV) acetylacetonate [Zr(C5H7O2)4], titanium(IV) isopropoxide {Ti[OCH(CH3)2]4} and lead(IV) acetate, [Pb(CH3CO2)4]. The crystalline quality of PZT thin films were measured by X-ray diffractometer and their ferroelectric properties were characterized based on hysteresis loop measurement. Finally, simulation confirms that PZT/AlGaN/GaN ferroelectric gate HFETs exhibit hysteretic I-V characteristics. Counterclockwise hysteresis was observed in the transfer characteristics, which is due to the ferroelectric switching effect of the PZT gate.