Epitaxial and ion-implantation techniques have been combined to form a high/low doping profile for GaAs Schottky-barrier Read-type IMPATT diodes. A c.w. output power of 1.1 W with 25% conversion efficiency was obtained at 11 GHz.

C.W. operation of ion-implanted GaAs read-type IMPATT diodes

We have designed, fabricated, and evaluated gallium arsenide Read IMPATT diodes for K a -band (36-38 GHz)operation. The devices were packaged units intended for manufacturability and high yield. Oscillator output power as high as 710-mW CW was obtained at 9-percent efficiency. This paper describes design and fabrication techniques employed and discusses the potential and limitations of such devices.

Millimeter-wave GaAs read IMPATT diodes

An analysis of the breakdown and capacitance properties of punch-through hyperabrupt epitaxial Schottky barrier diodes has been carried out. Results are given for the dependence of breakdown voltage of such a device on surface concentration and epitaxial layer thickness. Design curves are given for epitaxial hyperabrupt schottky varactor diodes. The design procedure yields an optimal impurity profile in which just-punch-through occurs at the highest voltage of operation. This gives a maximum dynamic range of operation still keeping the series resistance to a minimum. A corrected boundary condition to determine the profile constants associated with an n/n+ (high/low) junction is also given.

Breakdown and capacitance properties of hyperabrupt epitaxial Schottky barrier diodes

The avalanche breakdown voltage of a GaAs hyperabrupt junction diode is calculated by using unequal ionization rates for electrons and holes, and shown graphically as a function of the parameters which characterize the impurity profile of the diode. The breakdown voltage decreases abruptly at the critical point of the characteristic length L c which varies in accordance with the impurity concentration N 0 at x = 0. For example, the critical length L c is 7.7 × 10 −6 cm and 3.3 × 10 −5 cm for N 0 = 1 × 10 18 cm −3 and 1 × 10 17 cm −3 , respectively. The breakdown voltage of a diode with extremely short or long characteristic length can be estimated from the results for corresponding abrupt junctions. The experimental results agree well with the calculated ones.

Avalanche breakdown voltage of GaAs hyperabrupt junctions

Publisher Summary This chapter reviews that the most promising two-terminal devices are IMPATT diodes. They are particularly attractive in the oscillator-mode application. The preferential material for their fabrication appears to be GaAs. The lowest microwave frequency (1-5 GHz) would be preferably covered with TRAPATT diodes, guaranteeing high output power and high power efficiency, in any case where the high noise level peculiar to these devices can be accepted. The chapter also discusses that TEO is presently limited to the applications in the centimetric region requiring low output power and admitting low efficiency, mainly for the intruder alarm applications. In the millimetric range, power applications are currently limited to pumps for parametric amplifiers. BARITT diodes are only attractive because of their noise level, even lower than that of TEO. In contradistinction, their power output arid efficiency in the microwave range is definitely too small for power applications. Finally, varactor diodes being complementary devices are considered together with three-terminal devices that need such a complement for the time being.

Microwave Power Semiconductor Devices. II

Oscillation characteristics of GaAs Schottky barrier IMPATT diodes are studied by computer simulation. For a Schottky barrier- n-n + structure, the Read condition and the just-punch-through condition are found to be optimum with respect to the efficiency and power at 30 GHz. In order to improve the efficiency, a superabrupt doping profile is proposed and a high efficiency of 32 per cent is predicted. Calculation of the frequency dependence of the efficiency shows that GaAs IMPATT diodes still have the potentiality of high efficiency oscillator at 100 GHz and they are a promising microwave source in mm-wave region.

Michiharu Nakamura

Papers

Computer study on GaAs Schottky barrier IMPATT diodes

A High Power Gaas Schottky Barrier Impatt Diode in 30GHZ Band