FIELD: microelectronics. SUBSTANCE: invention refers to microelectronic technology and deals with test of quality of instrument silicon layers in compositions of silicon on dielectric " type. Method involves ellipsometric measurement of refractive index of films and quality of film is evaluated by character of its change while structure is heated from room temperature to 350-400 K. Structure is treated with ultrasound having frequency of 20-40 kHz in the course of 1-5 min in chemically pure inactive liquid prior to measurement of refractive index. EFFECT: enhanced sensitivity of ellipsometric test of silicon films on dielectric substrates for presence of defects. 1 tbl
