Submicrometer Self-Aligued GaAs MESFET (Short Papers)

Baudet, P.; Binet, Michel; Boccon-Gibod, D.

doi:10.1109/tmtt.1976.1128857

Cited by 19 publications

(3 citation statements)

References 4 publications

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“…The main requirement in selecting the gate metal is its etchability by wet chemical or plasma methods. Aluminum is a common choice for wet chemical etching (39,40) and refractory metals such as molybdenum are a common choice for dry plasma etching (41). The next step…”

Section: Closely Spaced Electrodes--lateral Etch Procedures-mentioning

confidence: 99%

A Review of GaAs MESFET Gate Electrode Fabrication Technologies

Weitzel

Doane

1986

J. Electrochem. Soc.

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This review is designed to give an overview of the processes that have been used to define gate electrodes for GaAs MESFET's. This is an important topic, because the size and structure of the MESFET gate basically determines the performance of the transistor, which in turn determines the performance of GaAs circuits. Therefore, considerable effort has been expended in developing a wide variety of techniques. This review covers some of these techniques: lift-off using a single layer of positive photoresist, lift-off using multilayer photoresist structures, deep UV and E-beam lithography, selfaligned processes, and some nonconventional techniques.

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Section: Closely Spaced Electrodes--lateral Etch Procedures-mentioning

confidence: 99%

A Review of GaAs MESFET Gate Electrode Fabrication Technologies

Weitzel

Doane

1986

J. Electrochem. Soc.

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“…An aluminum layer is evaporated on the Hall sample, which enables measurements to be made at several biases and gives the mobility vs. the thickness of the undepleted layer. MESFET devices were fabricated using a previously described technique (18) ; two geometries of devices are labeled A and B types in Table I.…”

Section: Experimental Conditionsmentioning

confidence: 99%

Device Quality GaAs Grown at Low Temperature by the Halide Process

Hallais¹,

Boccon-Gibod²,

Chane³

et al. 1977

J. Electrochem. Soc.

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A study of the parameters which must be controlled to enable the vapor growth of GaAs at low temperature (LT.VPE) using the AsC1JGaAs/H2 system has led to routine growth of MESFET layers at 630~ The source temperature was determined from transport efficiency measurements and set in the range 670~176The growth rate dependence on temperatures and the AsCI~ mole fraction were determined. The morphology of the layer was optimized as a function of the AsCh mole ~raction and the misorientation of the substrate. The best value of misorientation is about 6 ~ off (001). These growth conditions were applied to submicron layer growth, and MESFET devices were fabricated. A comparison of the device performances obtained on layers deposited at high (750~ and low (630~ temperature shows an improvement on unbuffered layers grown at low temperature. Furthermore, the growth of an n-buffer layer at low temperature improves the noise figure still further. Typical results without buffer layers, at 10 GHz, are 4 dB NF, 7.5 dB associated gain, and 11 dB maximum gain.The AsC13/Ga/H2 and AsC1JGaAs/H2 chemical vapor transport systems, first described by Knight et al. ( 1), are widely used for the epitaxial growth of device-quality GaAs. Most of the work is performed using deposition temperatures TD in the range 770 ~ 705~ (2-4), but for several reasons it becomes attractive to lower the source and deposition temperatures (TD < 700~ : Firstly, according to Weiner's calculation ( 5) and Di Lorenzo's data ( 6), silicon contamination is minimized at low temperatures; the second aspect is related to the thermal stability of GaAs (7). This last factor is of particular interest for MESFET devices for which submicron layers are deposited on semi-insulating substrates and whose rf performances and static characteristics are strongly dependent on the material and interface quality (8).Several workers (9, 10) have reported on new methods for low temperature epitaxy (< 700~ but most of their experimental conditions were based on out-of-equilibrium or out-of-steady-state conaitions. Their results suggest that undecomposed AsC13 molecules cause supplementary reactions which allow larger supersaturation.The aim of this work is: first, to define what can be expected for transport conditions in the temperature range 600~176and more particularly at 630~ which is near the congruent evaporation point of GaAs (11); and second, to define an optimum set of conditions for epitaxial growth and to apply it to the MESFET layers.

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“…Submicron microwave and millimeter-wave PET fabrication techniques can be used to form the gate and the source and drain ohmic contacts [9]-- [13].…”

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confidence: 99%