Electron field emission from SiOx films

Abstract

Efficient electron field emission from silicon flat cathode coated with SiOx film (x 0.3-0.5) was observed both before and after thermal (1000 °C) annealing with subsequent etching in HF solution. Oxide films were produced by silicon thermal evaporation in vacuum (10⁻⁵ Torr). Using optical spectroscopy in visible and infrared ranges, as well as AFM technique, structural features of these films were investigated. It was shown that initial SiOx film may be represented as SiOх (Si) composite (x 1.2). Thermal annealing causes further phase segregation in film material, and it is transformed into SiO₂ (Si) composite. During such a process, silicon grains size decreases and their density increases. The model of electron field emission from the surface of such films was proposed. It was supposed that limitation process of the current flow under high electric fields is connected with Fowler-Nordheim tunneling through barriers Si-SiOх-vacuum or Si-vacuum. Current peaks in emission I-V characteristics were explained in the framework of resonance tunneling mechanism. Investigated structures seems to be perspective for application as flat field cathodes in vacuum electronic devices and in flat panel field emission displays.