LOW-TEMPERATURE SIO2-FILMS DEPOSITED BY PLASMA ENHANCED TECHNIQUES

The use of silicon halides to obtain SiO2 films with plasma enhanced chemical vapor deposition (PECVD) techniques at low temperatures is reported. The silicon halides used were SiF4 and SiCl4. SiF4 was used in a direct PECVD system while a remote-PECVD (RPECVD) system was used with SiCl4. The deposition temperature was 250-degrees-C in the first case and in the range of 25-200-degrees-C in the second case. Optical measurements such as ir %T and ellipsometry and measurements of wet etch rate were used to characterize the films. It was found that the oxides were free of OH even for oxides deposited at the lowest temperatures. The electrical properties of the oxides were measured from metal-oxide-semiconductor structures fabricated with them. Breakdown fields for these oxides were typically of the order of 8 MV cm-1 and the fixed charge density in the range of 10(11)-10(11) charges cm-2.