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Mat. Res. Soc. Symp. Proc. Vol. 507 01998 Materials Research Society

torr. OES (optical emission spectroscopy) was installed for in situ plasma diagnostics. Film thickness and refractive index were measured by ellipsometer and film density was measured by microbalance. Film composition and chemical binding state were measured by XPS (X-ray photoelectron spectroscope) and RBS (Rutherford backscattering spectrometry). Surface roughness of the film was measured by AFM (atomic force microscope) and FT-IR (Fourier transform infrared absorption spectroscopy) was used to measure bonding configuration and bond concentration. Optical band gap (Eg) was obtained from UV-visible transmission spectra by using Tauc formula. The curvature of the substrate and the film was measured before and after the deposition with laser bending method for film stress. For electrical characterization, metal-insulator-semiconductor (MIS) capacitor was fabricated with deposited insulators. After Al electrode formation by evaporation, forming gas alloying was performed at 400'C. Current-voltage (I-V) characteristics was measured by HP 4145B semiconductor parameter analyzer. Temperature controller was installed in HP 4145B sample stage for the study of Arrhenius type conduction mechanism. Measurement temperature was ranged from room temperature to 150 0 C. Breakdown field from I-V curve was defined as the value at which the current is 1 jLA/cm 2 and also the resistivity was obtained at 2 MV/cm. RESULT AND DISCUSSION Homogeneous gas phase reaction and heterogeneous surface reaction should be identified to elucidate the deposition characteristics of the Si-N-H-F system. Plasma species including hydrogen (H 2*, H), Si hydrides (SiHx, x < 4), fluorides (SiFx, x < 4), nitrogen (N2 *) and ammonia (NHx, x < 3) were monitored by in situ OES. NH (336 nm) and atomic H (Haat 656 nm) were dominantly detected in NH 3 plasma in addition to molecular N 2* and charged N 2+ emission lines. In NH 3 plasma, N 2+ and atomic Ha emission lines increased slightly with the increment of plasma power, but intensity of NH, N 2* (337 nm) and most other peaks were saturated at the plasma power higher than 50W. In SiF 4-NH3 gas mixture, Ha emission intensity was significantly reduced below OES detection limit. It seems that the halide species generated from SiF 4 scavenges hydrides (NHx, H) in the gas phase. It is probably due to the HF formation, which is inactive in OES measurement. Figure 1 shows the OES spectra for SiHl-NH 3 and SiH 4SiF4 -NH3 systems. Atomic hydrogen decreased with SiF 4 addition while atomic F emission lines at 703 and 775 nm increased continuously. F '71 'NH

SiF SiH

"A 300

400

F (d)H

,(b) . , .500 600 700 (nm) Wavelength

472

, 800

Fig. 1 OES spectra for SiH 4 -NH3SiF4 gas mixture at SiH 4/NH3 :5/30 sccm, plasma power:50 W, SiF 4 (a)0 sccm, (b) 0.2 sccm, (c) 2 sccm and (d) 5 sccm

The emission intensities for NH, SiH, Ha, and F species as a function of SiF 4 addition are shown in Figure 2. NH and F emission was increased with the increase of SiF