FORMATION OF P-IN DEFECT IN ANNEALED LIQUID-ENCAPSULATED CZOCHRALSKI INP

Fourier transform infrared spectroscopy measurements have been carried out on liquid-encapsulated Czochralski-grown undoped InP wafers, whic h reproducibly become semi-insulating upon annealing in an ambient of phosphorus at 800-900 degrees C. The measurements reveal a high concen tration of hydrogen complexes in the form VInH4 existing in the materi al before annealing in agreement with recent experimental studies. It is argued that the dominant and essential process producing the semi-i nsulating behavior is the compensation produced by an EL2-like deep do nor phosphorus antisite defect, which is formed by the dissociation of the hydrogen complexes during the process of annealing. The deep dono r compensates accepters, the majority of which are shallow residual ac ceptor impurities and deep hydrogen associated V-In and isolated V-In levels, produced at the first stage of the dissociation of the VInH4 c omplex. The high concentration of indium vacancies produced by the dis sociation are the precursor of the EL2-like phosphorus antisite. These results show the importance of hydrogen on the electrical properties of InP and indicate that this largely results from low formation energ y of the complex VInH4 in comparison with that of an isolated V-In. (C ) 1998 American Institute of Physics.