Photocapacitance effects of deep traps in n-type InP

Abstract

Deep trapping centers in n-type InP samples grown by the liquid-encapsulated Czochralski, liquid-phase-epitaxial, and vapor-phase-epitaxial processes have been studied by photocapacitance techniques. Photocapacitance effects for Schottky barriers formed on these samples indicate four levels at 0.58, 0.78, 0.89, and 1.15 eV below the conduction band. Estimated trap concentration in various samples range from low-1014 cm−3 to the high-1012 cm−3. The broad increase in photocapacitance near 1.15 eV for all the samples may be associated with an intrinsic defect or phosphorus vacancy/impurity complexes. This result is consistent with the broadband present between 1.08 and 1.25 eV in photoluminescence experiments. The comparison between O2-doped and undoped VPE samples suggests the presence of oxygen located at about 0.78 eV below the conduction band in VPE material.

Photoconductivity in n-Type InP:Fe

“…I n these spectra it is related t o the residual oxygen impurities. I n the photocapacitance spectra of LEG-grown bulk I n P crystals and of LPE layers a level about 0.9 eV has been observed [9]. It corresponds to the transition E, in Table 1.…”

“…The transition E, is associated with the level of oxygen which lies about 0.8eV under the bottom of the conduction band. The level of oxygen has been established reliably by photocapacitance measurements of Schottky barrier structures of I n P : 0 [9]. I n these spectra it is related t o the residual oxygen impurities.…”

Deep Level in InP Crystal Grown by the Horizontal Bridgman Method under Controlled Phosphorus Vapor Pressure

“…Both levels were reported to be related to the Inrich composition. 10) Other levels related to intrinsic defects at E c − 0.64 or 0.74 eV + E v were not detected. We considered this to be due to the relatively high carrier concentrations of 2-4 × 10 16 cm −3 .…”

Deep Level Transient Spectroscopic Analysis on Au/SiO2/InP MOS Structures

“…Deep impurity levels in bulk InP have been studied by several workers using photocapacitance [1,2] and deep level transient spectroscopy studies [3 to 7]. However, interface states present in oxide/InP interface has not been thoroughly studied.…”