IMPROVEMENT OF THE PASSIVATION PROPERTIES OF SiO<sub>2</sub> FILMS, GROWN BY THE METHOD OF RAPID THERMAL ANNEALING, AFTER CHEMICAL RCA TREATMENT

Abstract

As it is known, increasing the efficiency of silicon solar cells is one of the most important tasks in modern alternative energy industry. Optimization of the antireflection and passivation layer is the most economical way to increase efficiency. In this work, the effect of pretreatment on the passivation properties of silicon dioxide (SiO 2 ) films grown by rapid thermal processing (RTP) at annealing temperatures of 900 and 950°C in a dry oxygen atmosphere, was studied. The growth of thin films of SiO 2 on the surface of monocrystalline silicon wafers was carried out in the AS-ONE 150 rapid thermal annealing chamber (France). Measurements of the lifetime of minority charge carriers by the non-contact microwave method showed that the best passivation of the samples is achieved by applying a preliminary three-stage chemical cleaning (RCA) of the surface of the n-type silicon wafers. IR spectroscopy confirmed the formation of a SiO 2 layer by the presence of an intense maximum at 1071 cm -1 , which was attributed to stretching vibrations of the "tensioncompression" type. The results of calculations of the optical constants of the obtained SiO 2 films using the reflection spectra and the SCOUT software show the presence of a silicon dioxide whose refractive index and extinction coefficient are close to the reference.