The electrical properties of as-grown low temperature (LT) GaAs grown at 200-300°C have been investigated in the temperature range of I O W 0 0 K. It was found that the resistivity of the LT GaAs layer increased as the growth temperature was increased from 200% to 300°C. Correspondingly, over the same growth temperature range, the breakdown field decreased from 320 kV cm-' !o 80 k\? E -' , yet WE more ? h a one order of magnitude higher than !het of semi-insulating GaAs. The breakdown voltage VeD was found to increase as the measurement temperature was decreased, differing from the behaviour of conventional avalanche breakdown. The transport properties of LT GaAs were characterized by hopping conduction at low electric field and low temperature. The particular properties of the as-grown LT GaAs layers suggest a useful application as an insulator in GaAs field effect transistors (FETS). The predominant ohmic behaviour, resulting from hopping conduction, produces a uniform field in the material, which prevents the breakdown at the gate edge of the FETS or at the surface. The high breakdown strength suggests enhanced performance in power devices.

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Articles you may be interested inEffect of thermal annealing on optical emission properties of lowtemperature grown AlGaAs/GaAs multiple quantum wells Annihilation of monolayer holes on molecular beam epitaxy grown GaAs surface during annealing as shown by in situ scanning electron microscopyThe effects of growth temperature and subsequent annealing temperatures on the electrical properties of the low temperature ͑LT͒ grown GaAs have been investigated. It was found that the resistivity of the as-grown LT-GaAs layer increased with increasing growth temperature, but was accompanied by a reduction of breakdown voltage over the same temperature range. Thermal annealing of the samples caused the resistivity to rise exponentially with increasing annealing temperature T A , giving an activation energy of E A ϭ2.1 eV. The transport of the LT-GaAs layers grown at T g р250°C was found to be dominated by hopping conduction in the entire measurement temperature range ͑100-300 K͒, but following annealing at T A Ͼ500°C, the resistivity-temperature dependence gave an activation energy of ϳ0.7 eV. The breakdown voltage V BD , for as-grown LT-GaAs was enhanced on lowering the measurement temperature, but conversely, decreased over the same temperature range following annealing at T A Ͼ500°C. The hopping conduction between arsenic defects, or arsenic clusters in annealed samples, is believed to be responsible for the observed electrical breakdown properties. Since the resistivities of the as-grown LT-GaAs layers are dependent, solely, on the excess arsenic, which in turn depends on the growth temperature, then the resistivities obtained can be used as a measure of the growth temperature.

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I-V properties of indium tin oxide (ITO)/p-InP solar cell structures measured at various temperatures show that the conduction mechanism is dominated by tunneling at low forward bias, and by thermionic emission at high forward bias. An increase of barrier height of 200–300 meV was found for all ITO/InP diodes compared with Au/InP Schottky diodes. Donorlike defects were found to be responsible for the increase of barrier height, and to cause the defect-assisted tunneling conduction. The experimental results support the model of a buried n+/p junction with the n+ layer induced by the sputter deposition of ITO.