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HL: Halbleiterphysik

HL 54: Bauelemente II

HL 54.1: Vortrag

Freitag, 28. März 2003, 11:45–12:00, BEY/81

The role of graded gap emitter in GaAs Gunn diodes — •Simone Montanari, Arno Fösters, Mihail Lepsa, Jürgen Stock, and Hans Lüth — ISG1 Forschungszentrum Jülich

Due to the increasing industry demand on microwave power sources, Gunn diodes, also known as transferred-electron-devices, are seen under a new light. Gunn oscillators combine low noise with excellent microwave power outputs; they exploit the negative differential mobility caused by inter-valley electron transfer (from Γ to L). High performance Gunn diodes are based on a graded gap emitter. Even though this special emitter has been introduced more than ten years ago, its physical and high frequency behaviour is not completely clear.

Several GaAs Gunn layer structures have been investigated with the focus on the role of the graded gap emitter. Normally diodes are processed and mounted in an oscillator. This approach is not suitable for a deep analysis of the Gunn effect, because all the high frequency data are strongly influenced by the resonator of the oscillator. For this reason diodes have been processed in two different ways: vertical diodes to be directly built into an oscillator and planar ones for on-wafer measurements. A complete characterization (I/V, pulsed, CV, and S-parameters) has been performed on the planar structures to better understand the emitter behaviour from DC to 110GHz.