Novel planar Gunn diode operating in fundamental mode up to 158 GHz

Impact ionisation electroluminescence in planar GaAs-based heterostructure Gunn diodes: Spatial distribution and impact of doping non-uniformities

“…Fundamental mode operation at frequencies as high as 158 GHz have already been demonstrated from these devices 4 .…”

“…The active length of the device was defined during the fabrication by the deposition of the metallic ohmic electrodes and the devices where isolated by mesa chemical etching. More details on the growth and fabrication of these devices can be found elsewhere 4 . The Gunn devices were tested on-wafer at room-temperature and under DC bias.…”

Planar gunn diode characterisation and resonator elements to realise oscillator circuits

“…The planar construction of the Gunn diode is shown as a schematic in Figure-1 and was developed by the Universities of Glasgow and Aberdeen [1][2][3][4], The device material layers were grown by mo lecular beam epitaxy (M BE) and fro m top to bottom in Figure 1 consist of a highly doped GaAs layer (15n m), the active channel region consisting of 50n m of un-doped GaAs between 20n m layers of double δ-doped Al 0.23 Ga 0.77 As, 50n m GaAs buffer layer g rown directly to a 620 µm thick semi-insulating GaAs substrate. The metal anode and cathode ohmic contact regions were defined by electron beam lithography using polymethylmethacrylate (PMMA) resist and formed using Pd/ Ge/Au/Pt/Au deposited by e-beam evaporation and annealed at 400ºC.…”

“…The device structure was compatible with waveguide or coaxial circuits but difficult to integrate into a p lanar circuit technology, for example microstrip and coplanar waveguide (CPW). In recent years a planar diode has been developed [1][2][3][4][5], in which the anode and cathode contacts are on the top surface of the semiconductor making it d irectly co mpatible with coplanar waveguide technology. This has enabled for the first time Gunn diode technology to be explored in p lanar form, for examp le Monolithic Microwave Integrated Circuits (MMICs).…”

“…This has enabled for the first time Gunn diode technology to be explored in p lanar form, for examp le Monolithic Microwave Integrated Circuits (MMICs). The fundamental frequency of the planar Gunn diode operation is controlled by the distance between the cathode and anode contacts and recent work has shown that fundamental frequency of 158GHz [1] can be achieved in galliu m arsenide (GaAs). By reducing the gap and exploring harmonic extraction the device could provide a low cost integrated milli-metric and tera-hertz source.…”