A QUANTITATIVE STUDY OF CHEMICAL ETCHING OF INP

Chemical etching of InP with HCl is used on a large scale, but limited information is available in the literature on the quantitative and me chanistic aspects of this reaction, A higher reaction rate is observed in alcoholic HCl than in aqueous HCl solutions. Also, a decrease of t he reaction rate is observed with an increase in the degree of dissoci ation of HCl in aqueous solutions. We confirm that chemical etching de pends on the concentration of nondissociated HCl molecules and that th e reaction does not occur below a critical concentration. A first-orde r rate was obtained in aqueous and in alcoholic HCl solutions. The Arr henius plot indicated an activation energy greater than 40 kJ . mol-1, indicating a kinetically controlled process. Scanning electron micros copy also showed profiles characteristic of a kinetically controlled p rocess.