Preparation of Thin-Film Silicon Dioxide by RF Sputtering

摘要

The results of a study on the deposition of thin-film silicon dioxide by RF sputtering are discussed. The dielectric source material was quartz which was sputtered and deposited onto aluminum electrodes and counterelectroded to complete the metal-oxide-metal capacitive structures. Depositions were conducted at pressures from 1-20 x 10 to the -3 power torr utilizing a triode type sputtering system wherein the processes of ionization of the gas and bombardment of the material are separated essentially. An electron beam is used to ionize the gas and produce the plasma. Application of an RF voltage (13.560 MHz) to a conducting plate placed behind the dielectric (quartz) plate translates the RF power by displacement current through the insulating source material. Interaction of RF voltage and plasma results in the establishment of a dc field between source and plasma which allows for the sputtering of the insulator. The capacitors were utilized to evaluate the dielectric, the device characteristics, and related process parameters. The effect of gas sputtering pressure, magnetic field strength, source-to-substrate distance, and power density on the rate of deposition is shown. Increased film thickness uniformity over a 3 in x 3 in area by optimum substrate positioning is indicated. Dielectric constant, dissipation factor, dielectric breakdown strength, insulation resistance, heat treatment, capacitance and dissipation factor over the range 400 Hz to 5 MHz, and effect of coating on thin-film resistive elements are reported. (Author)