AVS 46th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS-MoP

Paper PS-MoP1
A-Si:H Film Deposition Using Plasma CVD with Suppression of Cluster-Size Particles

Monday, October 25, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: M. Shiratani, Kyushu University, Japan
Authors: M. Shiratani, Kyushu University, Japan
S. Maeda, Kyushu University, Japan
Y. Matsuoka, Kyushu University, Japan
K. Tanaka, Kyushu University, Japan
K. Koga, Kyushu University, Japan
Y. Watanabe, Kyushu University, Japan
Correspondent: Click to Email
In order to deposite high quality a-Si:H at a high rate using SiH@sub 4@ RF discharges, we have developed methods for suppressing cluster-size particles, which are believed to degrade film quality. We have examined effects of pulse modulation of discharges, heating of the GND electrode as well as H@sub 2@ dilution on growth of particles by using two novel in situ methods@footnote 1,2@ for determination of size and density of cluster-size particles below 10 nm in size. Even under so-called device qualtiy conditions, particles have begun to be observed around the plasma/sheath boundary near the RF electrode and mainly grow in the same region. They grow at a growth rate of 10 nm/s, much higher than a typical film deposition rate of 0.1 nm/s, and their density is above 10@super 10@ cm@super -3@. We also have studied effects of GND electrode heating on suppression of particles in modulated discharges. While the modulation without heating the GND electrode brings about suppression of particle growth, the modulation with heating the GND electrode to 200C realizes deposition without cluster-size particles during more than 1 hour even for a relatively high duty cycle of 63% (t@sub on@=5 ms). This notable suppression of particle growth with the heating can be explained by a model taking account of thermophoretic force exerted on particles. High H@sub 2@ dilution (>80%) has been revealed to be effective in suppressing growth of cluster-size particles especially around the plasma/sheath boundary near the RF electrode. Correlation between particle density and film quality will be presented. @FootnoteText@ @footnote 1@M. Shiratani and Y. Watanabe., Rev. Laser Eng., 26 ( 1998) 449. @footnote 2@T. Fukuzawa, et al., J. Appl. Phys., 80 (1996) 3202.