Deep-level transient spectroscopy studies of near-surface hole and electron traps in Zn-doped InP using high barrier Yb/p-InP Schottky diodes

High barrier Yb/p-InP Schottky diodes were used to study hole and electron traps in Zn-doped p-InP single crystals by deep-level transient spectroscopy (DLTS). DLTS spectra were recorded at different quiescent bias voltages in the temperature range between 80 and 450 K. From the DLTS measurements at reverse bias of 3 V, three hole traps, H₁ (E_V +0.56 eV), H ₂ (E_V +0.22 eV), H₃ (E_V +0.12 eV), and one electron trap, E₁ (E_C -0.40 eV) were observed. The concentration of the traps ranged between 10¹² and 10¹⁵ cm^-3 with a capture cross section between 10^{- 19} and 10^-17 cm ². The DLTS spectra, at a quiescent forward bias of 0.2 V, revealed only one interfacial hole trap (E_V +0.25 eV) which was different from the hole trap H₂. The measurements at different reverse bias values on the most prominent hole trap indicated an anomalous field dependence of the DLTS signal which suggested that the concentration of the trap level decreased and its activation energy as well as capture cross section increased with depth from the metal-semiconductor junction.