1983 · 11 citations · 0 references
EngineeringElectrical EngineeringMaterials ScienceMicroelectronicsSemiconductor DevicesSemiconductor MaterialsMetal-semiconductor ContactsMetalsSemiconductor Device MaterialsSemiconductor PhysicsSemiconductor Thin FilmsThermal Properties Of SemiconductorsAnnealing Temperature EffectsGaas Microwave Integrated CircuitsIon Implantation EffectsMetal Gate ElectrodesRefractory Metal AlloysSemiconductor CharacterizationThermal StabilityTransconductance
Sputter deposited W-Al alloy film was found to be a low-resistive and thermally stable refractory gate metal for GaAs MESFET. The resistivity of 1000Å thick film is 40pftcm, and it forms good Sohottky contact with n-GaAs even after the annealing at 900°C. Using this gate metal, high-performance self-aligned FET's can be fabricated reproducibly. Maximum transconductance achieved in D-FET was 200mS/mm for V <inf>T</inf> =-0.45V, L <inf>g</inf> =1.2µm and ion implantation energy of 60keV. An E/D gate ring-oscillator showed minimum delay time of 25ps/gate with power dissipation of 2.6mW/gate. This paper shows thermal stability of the new refractory gate metal, W-Al alloy film first. Reproducible FET fabrication process, the results of high-g <inf>m</inf> self-aligned FET <sup>1</sup> s and speed performance are involved in this paper.