Can Be Low-voltage Drive Of Barium Titanate Thin Film Field Emission

Display device is turning its way to flat panel display. Field emission display (FED) is an excellent technology which would lead to a significant change in the display industry. The key technology of the FED is to develop a cold cathode with high brightness under low driving voltage. Here we propose a new structure of cold cathode based on ferroelectric materials and thin metal films,and the gate hole is lower than 100 nm and the driving voltage will be much smaller. We utilized a thin metal film with net structure as gate electrode and barium titanate (BaTiO3: BT) film instead of oxide layer in the metal-oxide-semiconductor (MOS) structure.The BT films were deposited on silicon substrates by radio frequency magnetron sputtering system and the performance of the films were characterized by Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS) and X-ray Diffraction (XRD). Gold films as thin as 15 nm were evaporated on the BT films as gate electrodes. The field emission was measured in high vacuum chamber after introducing an anode that was applied a high voltage to collect the emitted electron. When the gate bias was higher than about 3V, the electron emission was observed. The electron emission follows F-N theory. However emission efficiency was very low, only about 0.0001%. Simulation of the Spindt electron emitter with small gate hole was made with finite element method. The simulation results show the emission efficiency is higher than 20%. Comparing to the simulation results, the low efficiency experimentally observed is contributed to large leakage current of gate electrode. An improved structure was proposed to decrease the leakage current and then the emission efficiency will be increased.