Speaker
Description
Gallium arsenide (GaAs) remains a key material for optoelectronic and high-speed electronic applications, including laser diodes, infrared light-emitting diodes, solar cells, and high-frequency switching devices. In this study, electrically active defects in Si-doped n-type GaAs are investigated using conventional Deep Level Transient Spectroscopy (DLTS), Laplace DLTS, and Admittance Spectroscopy.
Palladium (Pd) Schottky barrier diodes (SBDs), 0.5 mm in diameter and 150 nm thick, were fabricated on 5 µm Si-doped n-GaAs layers grown on n⁺-GaAs substrates (Spire Semiconductor). Current–voltage (I-V) measurements show low reverse leakage currents, confirming good diode quality, while capacitance–voltage (C-V) profiling indicates a uniform carrier concentration of ~1.2 - 1.4 × 1015 cm-3 over a depth range of 1 - 3.5 µm.
Conventional DLTS measurements reveal that the reference material is dominated by the well-known EL2 defect, with no additional deep levels detected. Following electron irradiation, several additional defect states are introduced. Particular attention is given to the dynamic behaviour of the EL2 defect. High-temperature DLTS measurements (>350 K at 80 Hz) confirm its presence, while Laplace DLTS is used to resolve changes in its fine structure before and after electron irradiation at varying fluences.
Trap concentrations were evaluated using a double-pulse DLTS technique, and the results were correlated with admittance spectroscopy measurements. The combined approach provides insight into the configurational complexity and defect interactions associated with EL2, particularly under irradiation-induced conditions.
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