Microfabrication of Field Emission Devices for Vacuum Integrated Circuits using Orientation Dependent Etching

Abstract

ABSTRACTVacuum integrated circuits and field emission (FE) devices with geometries on the micron and submicron scale have been discussed as alternatives to solid state devices for high speed and hostile environment application as well as for miniature electron sources for CRTs. These miniaturized vacuum devices have been developed on the basis of the advances in micromachining technology, i.e. orientation-dependent etching (ODE) of lithographically patterned silicon. This paper describes the ODE methods used to fabricate pyramidal electron emitter points 1.5 μm high, with radius of curvature of 20 to 100 nm from <100> silicon. In order to reduce operating voltages, an integral extraction electrode (grid) was fabricated by a self-aligned technique. With a single gate mask level the extraction and planar collector structures were fabricated on chip, to form a planar vacuum triode. The final mask step provided the flexibility for fabricating a variety of planar vacuum integrated circuit elements.