Electron emission from ferroelectric thin film cathodes

Summary form only given. Thin film ferroelectric cathodes have been proposed for several applications, such as flat panel displays. For this application, electron emission currents of 10s of mA/cm/sup 2/ will be required. Strong pulsed electron emission from bulk ferroelectric cathodes has been widely reported (100s of A/cm/sup 2/), but reports on thin film ferroelectric cathodes have shown that only relatively small currents (/spl sim/0.1 /spl mu/A/cm/sup 2/) are obtainable when the thickness is reduced to a few microns. Because of the attractive advantages of thin film cathodes in flexibility and low switching voltage, we are systematically studying ways to improve the emission performance. Three kinds of ferroelectric thin film cathodes have been fabricated: PLZT 2/95/5 (0.15 /spl mu/m thick), PNZT 4/20/80 (0.8 /spl mu/m), and PLZT 25/10/90 (0.15 /spl mu/m). Standard microelectronic techniques were used to make the devices. The top electrodes were patterned into strips that have equal width and spacing between strips. For comparison, three patterns of different electrode strip width, 1.5 /spl mu/m, 3.0 /spl mu/m, and 10 /spl mu/m, were made for each material. The electrode strip widths used are much smaller than those reported by others (200-300 /spl mu/m) and are a close match to the thickness of the film. This has been suggested in the literature to produce higher emission.