AVS 47th International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS-MoM

Paper PS-MoM6
Studies on SiF@sub x@ Radicals in Fluorosilane Plasmas Used for Silicon Etching and Deposition

Monday, October 2, 2000, 10:00 am, Room 311

Session: Plasma-Surface Interactions I
Presenter: K.L. Williams, Colorado State University
Authors: K.L. Williams, Colorado State University
E.R. Fisher, Colorado State University
Correspondent: Click to Email
Fluorosilane plasmas have been used in the microelectronics industry for etching of Si/SiO@sub 2@ and for deposition of fluorinated silicon alloys, such as a-Si:H,F. Specifically, fluorinated a-Si films are used in the fabrication of solar cells, photoreceptors, and thin film transistors. In spite of high quality film production, there is still controversy over the mechanistic aspects of deposition processes. Moreover, fundamental chemical and physical information on plasma species such as SiF@sub x@ radicals is not available. The surface reactivity of SiF and SiF@sub 2@ radicals during plasma processing of silicon-containing substrates using the Imaging of Radicals Interacting with Surfaces (IRIS) technique is reported. The molecular beam sources are 100% SiF@sub 4@, 90/10 SiF@sub 4@/H@sub 2@, and 50/50 SiF@sub 4@/H@sub 2@ plasmas. SiF and SiF@sub 2@ have been studied as a function of applied rf power (20, 40, 80, and 170 W) in each of these plasma molecular beams. Initial reactivity measurements of SiF on a Si substrate demonstrate that applied rf power has a significant effect on SiF scatter, which ranges from S = 0.05 at 20 W to S = 0.70 at 170 W. A S < 1 indicates that there is surface loss of SiF. Several possible mechanisms exist which may explain surface loss of SiF . These possible mechanisms will be discussed along with IRIS results for both SiF@sub 2@ and SiF scatter. Furthermore, IRIS results can be correlated with data from film characterization by Fourier transform infrared spectroscopy (FTIR) and profilometry of films deposited under various plasma parameters (applied rf power and % H@sub 2@ addition).