Mesa-isolated GaAs Schottky-barrier photodiodes

The design, fabrication and characterisation of GaAs Schottky-barrier phtodiodes with evaporated, free-standing metal airbridges is reported. The photodiodes were farbicatied using all dry-etching techniques. Anisotropic chemically assisted ion beam etching was used to etch vertical sidewall measas, and istropic reactive ion etching was used to etch a lateral tunnel. A free-standing-metal airbridge created by the lateral tunnel etch results in isolation of the active area at the same time, providing free-standing-metal interconnection to the contact pad.