Characterization of a defect layer at a Schottky barrier interface by current and capacitance measurements

Abstract The electrical properties of a Ti/GaAs Schottky diode were investigated using electrical measurements under forward bias. The current, the low and high frequency capacitance and DLTS measurements evidence and describe in a consistent way the existence of a thin layer of defects induced by the metal deposition process near the interface. The quasi-saturation of the current and the excess low frequency capacitance are analysed by means of a generalization of a dipole layer model. The high density of states extending for several hundreds of Angstrom in the semiconductor is also evidenced by high frequency capacitance measurements. DLTS measurements using positive pulses confirm the presence of the traps and, together with the temperature analysis of the cut-off frequency, allow to study the trap emission process over a wide range of temperatures.