Ion layer gas reaction (ILGAR) -: conversion, thermodynamic considerations and related FTIR analyses

Recently ion layer gas reaction (ILGAR) has been introduced, a novel deposition technology for thin sulfide and oxide layers. Since there is typically incomplete conversion of the educt, thermodynamic calculations were carried out to elucidate the stability ranges of the desired products. It is only deeper in layers, where by-products are less easily removed and the situation resembles more a closed system, that the equilibrium can shift towards the educts. Interestingly, thermodynamic calculations predict e.g. zinc oxide as the stable product for the ILGAR oxide process even at room temperature. Nevertheless, FTIR and XRD clearly identified the formation of zinc hydroxide at 25degreesC which dehydrates completely already at 155degreesC. ILGAR therefore opens the possibility of preparing mixtures of hydroxide and oxides of well defined ratios by adjusting process temperature and duration. Several possibilities were successfully tested for elimination of by-products or educt residuals from the layer. (C) 2002 Elsevier Science B.V. All rights reserved.