Vacuum Microelectronic Emitters and Their Applications Using CompoundSemiconductor Technology

摘要

Vacuum microelectronic devices (VMDs) are a class of devices in which electrontransport occurs both in semiconductors and in vacuum. They have the potential of combining the advantages of vacuum tube based devices with those of modern semiconductor devices. The key to the success of VMDs is fabricating reliable solid state electron emitters with high emission efficiency and high emission current density. This report will present the design, growth, fabrication and characterization of Planar-Doped-Barrier Electron Emitters (PDBEEs) made of compound semiconductor AlGaAs/GaAs. In PDBEEs, electrons, as majority carriers, are injected over a triangular barrier into a high field region accelerated towards the surface. Injected Electrons gain kinetic energy from the field and lose kinetic energy through scattering processes. Those electrons with enough energy to overcome the surface barrier upon reaching the surface could be emitted into vacuum. The surface work function of semiconductors (GaAs in this work) is lowered by cesiation. An emission efficiency of 4.2 percent and an emission current density of 5.8 A/cm(2) have been obtained from Al(0.3)Ga(0.7)As/GaAs PDBEEs. (MM).