Electron emission from silicon tip arrays controlled by np junction minority carrier injection

• Published in: Journal of vacuum science and technology. B, Nanotechnology & microelectronics Nanotechnology & microelectronics, 2010-09, Vol.28 (5), p.1060-1065
• Main Authors: Young, Robert M., Nathanson, Harvey C., Howell, Robert S., Stewart, Eric J., Nechay, Bettina A., Braggins, Timothy T., Graves, Eric M., Van Campen, Stephen D., Clarke, R. Christopher, Miserendino, Scott B., Hawk, Jonathan
• Format: Article
• Language: English
• ISSN: 2166-2746; 2166-2754
• DOI: 10.1116/1.3490404

The authors demonstrate for the first time the injection of electrons across an n-type to p-type silicon junction and their subsequent tunneling from approximately 1 μm tall p-type silicon points into a vacuum gap. The diffusive flow of these minority carriers in the p-type material is controlled by the application of a bias voltage in the form of a base contact metallization contact on the p-type silicon, in analogy with a bipolar junction transistor. Using an array density of 4×106 tips/cm2, the authors measured a maximum average current of 1 nA per tip. Increasing the base contact bias voltage from 0 to ∼1 V changes the emission from a supply limited regime typically observed with p-type silicon emitters, bringing the emitted current back to a linear Fowler–Nordheim characteristic similar to that observed previously by photon generation of carriers in p-type silicon tips. The authors finally note that in our short tips, minority carrier flow should be a nondissipative largely adiabatic diffusive transport process which is followed by extraction into vacuum. A novel heat extraction mechanism for future cooling applications is thus anticipated.