Sriram Ramamoorthi

Polysilicon metal-insulator-semiconductor electron emitter

The flat metal-insulator-semiconductor (MIS) electron emitter is a simple design, allowing easy manufacture. The emitters are relatively insensitive to environment, allowing them to operate in poorer vacuum conditions than are necessary for oxide thermionic or microtip field emitters. In most literature reports, MIS and metal-insulator-metal devices are limited in emission current ( 400pores∕μm2 through which electrons a...

Novel flat MIS electron emitter

The flat metal-insulator-semiconductor (MIS) electron emitter is a simple design allowing easy manufacture, and is relatively insensitive to environment conditions making operation possible in poor vacuum conditions. A stack of 5000 /spl Aring/ polysilicon/150 /spl Aring/ silicon oxide/50 /spl Aring/ gold deposited on n++ doped silicon showed the best performance. We have observed emission current densities as high as 2-10 A/cm/sup 2/ at efficiencies from 3-10%. The polysilicon serves a dual role. Bumps on the poly surface act as field-enhanced emission sites while the bulk of the film behaves as a ballast resistor that prevents run away emission from any one emission site. The thin gold layer self-assembles into a nano-mesh with >100 pores//spl mu/m/sup 2/ through which electrons escape. Emission theory, including energy distribution and angular divergence of the emitted beams, are discussed.