A tunable-frequency Gunn diode fabricated by focused ion-beam implantation

The fabrication of a planar Gunn diode in which the fundamental transit-time model oscillation frequency can be tuned over the range 6-23 GHz by varying the DC bias across the device is reported. The wide-band tunability is due to a linear doping-concentration gradient between the contacts. This lateral doping is created by implanting the device with a focused beam of silicon ions and smoothly increasing the dose from contact to contact. A Gunn diode with a uniform active region, also fabricated with the focused ion beam, displays a relatively constant oscillation frequency in the same bias range.<
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