High-purity InP and the role of hydrogen

Abstract

Extremely high-purity InP has been grown in an atmospheric-pressure MOCVD reactor over the unusually large temperature range from 575-700°C. T h e apparent purity of the material was enhanced by the incorporation of atomic hydrogen. At 650°C. a temperature at which many device structures are grown, a 77 K electron mobility of 190 000 cm2 V-' s-' was obtained with an electron concentration of 1.6 x c r r 3 . Removal of the hydrogen resulted in a decrease in the electron mobility and an increase in the electron concentration. After removal of the atomic hydrogen, samples grown at 650 "C had 77 K electron mobilities01 -140000cmZV-' 5 -' at an electron concentration of -3.6 x lO'"cm-'. Analysis of the temperature dependence of t h e electron mobility indicates that the atomic hydrogen, which comes from the thermal decomposition of the phosphine on epilayer cool-down,neutralises both donors and acceptors. The incorporation and removal of hydrogen does not affect the optical characteristics of the material as measured by DhotolumineScence and far-infrared photoconductivity.

Growth of InP in a Novel Remote-Plasma MOCVD Apparatus : an Approach to Improve Process and Material Properties

“…The most important feature is the lower oxide layer thickness (24 1) for the InP8-plasma sample than that for samples deposited under conventional conditions (# InP2, # InP6). The formation kinetics of the native oxide layer can be used to speculate on the effectiveness of H2-PH3 plasma in passivating and stabilizing the InP surface [24]. In addition, the sample (# InP2) deposited at high VIIII ratio (=150) and low temperature (550°C) shows a complex multilayer structure on a disordered InP epilayer film which includes 2% of voids.…”

Phosphorus ablation process as a hydrogen atom probe in a remote H2 plasma reactor

“…In particular, H atoms surface chemistries include: ͑i͒ the assisted decomposition of precursor molecules to improve the deposition processes, 1 ͑ii͒ the etching of carbon contamination as CH 4 for the stabilization of surfaces and structures, 2 ͑iii͒ the reduction of the surface native oxides for substrates cleaning, 3 and ͑iv͒ the material hydrogenation for defect saturation and passivation. 4 However, the H-atom flux interacting with the surface needs to be appropriately chosen and controlled to maximize defect passivation, to optimize native oxide removal, and to avoid material damage, i.e., rough morphology and, for InP, the preferential etching of phosphorus, causing consequential loss of stoichiometry.…”