Polysilicon metal-insulator-semiconductor electron emitter

Abstract

Articles you may be interested inAnalysis of temperature dependent current-conduction mechanisms in Au/TiO2/n-4H-SiC (metal/insulator/semiconductor) type Schottky barrier diodes Hydrogen interaction with platinum and palladium metal-insulator-semiconductor devices J. Appl. Phys. 98, 014505 (2005); 10.1063/1.1953866Metal-insulator-semiconductor emitter with an epitaxial CaF 2 layer as the insulator J.The flat metal-insulator-semiconductor ͑MIS͒ 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 ͑Ͻ0.001 A / cm 2 ͒ by their low efficiencies ͑Ӷ0.1%͒. We have observed emission currents as high as 2-10 A/cm 2 at efficiencies from 3 % -10%. Our best results are from emitters comprised of 5 -7.5 nm gold/ 15 nm SiO 2 / 100 nm polysilicon/n ++ doped silicon substrate. The roles of each component of the flat emitter were investigated. The polysilicon serves a dual role: Bumps on its surface act as field-enhanced emission sites while the bulk of the film behaves as a self-adjusting ballast resistor preventing run away emission from any one emission site. The thin gold layer self-assembles into a nanomesh with Ͼ400 pores/ m 2 through which electrons are emitted. Energy distribution and angular divergence of emitted electrons were measured. A coherent explanation of emission including the origination of the divergence is presented. Pros and cons of the MIS emitter and potential application are discussed.

(Invited) Electron Emission Study of Planar-Type Electron Emission Devices Based on Nanocrystalline Silicon

“…Improving the performance of the MOS electron emission device, it is very important to suppress electron scattering within the oxide and the gate electrode, and to reduce the work function of the gate. Decreasing the topmost electrode thickness to reduce electron scattering within the electrode and utilizing the insulating film consisting of nano-and micro-crystalline silicon (11)(12)(13), in which the injected hot electrons would quasi-ballistically transport, taking the place of the oxide layer, have been proposed to improve the emission efficiency. Recently, the high emission current density of 1-100 mA/cm 2 and the high electron emission efficiency of over 10 % have been reported for a graphene-oxide-semiconductor (GOS) structure by suppressing electron scattering within the topmost gate electrode using a graphene electrode synthesized directly on the oxide layer (14).…”

P1–24: Photo-assisted electron emission from MOS-type cathode based on nanocrystalline silicon

“…In fact, a large number of electrons have been detected at energies lower than the original work function of the gate metal by cesiation [4]. The modified MOS-type cathodes were reported to have high efficiencies over 10 % [5,6]. In those cathodes, the oxide layer is replaced with oxidized films containing nano-or poly-crystalline silicon.…”

Charged Particle Ejection from Nanolayered Heterostructures

“…The reason for the poor performance of Ti/Au and Cr/Au combination might at least partly be explained by the reactive nature of the interface. Govyadinov et al 35 have screened several combinations of metals for the top electrode in a polysilicon MIS electron emitter and experimentally determined that porous metal film improved the emission efficiency of the MIS device compared to a device with dense continuous metal layer as the top electrode. In our studies of devices with Ti/Au or Cr/Au as the top metal electrode, the wetting layer will promote formation of a more uniform Au layer and thus, similar to the observation by Govyadinov et al, decrease the emission current.…”