Sealed vacuum electronic devices by surface micromachining

Solid-state planar micromachining techniques have been applied in the fabrication of two types of vacuum microelectronic devices. Cold-cathode devices based on field emission and hot-cathode devices based on thermal-field emission have been fabricated for possible use in high-speed, high-operating-temperature device applications. Polycrystalline silicon has been used as the cathode, anode, and gate material in these device structures. On-chip vacuum-sealed cavities have been formed through the micromachining of polycrystalline silicon microbridges. An elevated and sealed polycrystalline silicon emission filament has also been formed by surface micromachining techniques. The measured transconductance of the hot-cathode triode is 3.4 mu A/V. Device operation and measured current versus voltage characteristics are presented for these devices.<>