THE PHYSICS OF FIELD-EMISSION IN THE CONTEXT OF VACUUM MICROELECTRONICS

It is well known that surface treatments and cathode geometry affect the stability and strength of field emission (FE). The development of sub-micron electron sources requires research on the strength, stability and controllability of emission from areas of a few nanometres in diameter. The influence of cathode radius and surface layers on FE has been studied theoretically showing strong deviations from Fowler-Nordheim behaviour at low voltages. The interaction of a tunnelling electron with the charge density in the emitter, is also responsible for modifications in the surface potential. There is a characteristic response time for changes in the charge density and therefore it is of importance to be able to estimate the time that an electron spends tunnelling. An approach to the problem using Stochastic Mechanics is introduced and discussed in the context of other theories of the tunnelling time. Electron transport in a semiconductor depends on the doping concentration. Results are presented on the narrow width of the FE energy distribution and explained by the narrow energy spectrum of the supply of electrons to the surface for highly doped silicon.