Undoped Silicon Dioxide Research Articles

TEOS-PECVD system for high growth rate deposition of SiO 2 films

The Plasma-enhanced chemical vapour deposition (PECVD) system has been developed for the deposition of doped and undoped silicon dioxide (SiO 2) films at high growth rates. The deposition chamber with symmetric parallel plate reactor has been designed and fabricated on the basis of some assumptions. The process parameters have been optimized for the growth of SiO 2 films. The films were deposited by present PECVD system using tetraethoxysilane (TEOS) as a source of Si and characterized by ellipsometery and FTIR spectroscopy. The comparative study of reactor geometry, process parameters and growth rate of present system with that of the PECVD systems reported in the literature has been presented. The growth rate obtained by our home-made system has found to be higher than that of the other reported PECVD systems. The positions of the characteristic peaks of the FTIR spectra, of the SiO 2 films deposited by the present system have also been compared with that of the other systems and consistency has been observed, which proves the validity of the system. From comparison and experimental results it is revealed that the present PECVD system proved to yield high growth rates for the deposition of good-quality SiO 2 films with higher thickness essential for optoelectronics applications.

The effects of PECVD silicon dioxide passivation on the electrical characteristics of Sol-Gel deposited PZT film capacitors

Abstract Plasma-enhanced chemical vapor deposition (PECVD) of doped and undoped silicon dioxide layers is widely used throughout the semiconductor industry for the passivation of processed devices before the final metallization processing steps. However, a reduction in the remanent polarization of PZT platinum-electrode capacitors has been observed when the capacitors were passivated with PECVD silicon dioxide films. This paper presents the results of a study to determine the effects of a standard PECVD silicon dioxide process on the retained polarization of Sol-Gel derived PZT capacitors with platinum electrodes. The retained polarization of the capacitors was measured before and after the silicon dioxide depositions. Measurements indicate that for PZT capacitors with temperature-stabilized top electrodes, there is relatively little change in the retained polarization after the depositions. However, for the PZT capacitors without the temperature-stabilized top electrodes, reductions in excess of 70% in t...

Isotropic plasma etching of doped and undoped silicon dioxide for contact holes and vias

Isotropic plasma etching of doped and undoped oxides has been studied as an alternative to the ‘‘wet’’ isotropic step in the ‘‘wet–dry’’ contact etch approach. Czochralski grown p-type 〈100〉 100-mm-diam silicon substrates with either 0.1-μm low-temperature chemical vapor deposition oxide (LTO) and 0.5-μm borophosphosilicate glass (BPSG, 2.5 wt. % B and 7 wt. % P), or 0.6-μm thermally oxidized silicon were used. These substrates were masked with a resist pattern with contact holes whose diameters were between 10.0 and 0.75 μm. Subsequently, they were isotropically etched in a Matrix System One etcher. In this step 0.3 μm of the oxide was removed. The remaining oxide was anisotropically etched in an AME 8110 hexode etcher in a CHF3 / CO2 /He mixture at 72 mTorr and 1250 W. The isotropic oxide etch process was characterized using a multilevel statistical experimental design with pressure, 13.56-MHz rf power, and total gas flow (50% NF3 in He) as the variables. Optimized etch conditions resulted in an etch rate uniformity of less than ±3.0% (one sigma divided by the average for 9 points), a BPSG etch rate in excess of 0.3 μm/min, a thermally oxidized silicon etch rate of 0.12 μm/min, and a resist etch rate of <14 nm/min. The scanning electron miscroscope measurements showed a critical dimension variation of <0.1 μm total in the contact hole diameter at the LTO–silicon interface as compared to the contact hole diameter at the resist–BPSG interface before etch.

Dc leakage currents in trichloroethylene oxides

Undoped silicon dioxide is compared to oxide in which trichloroethylene (TCE) was used during growth. The gate leakage currents in MOS transistors are examined. It is shown that a reduction in the leakage current occurs in TCE oxides. A novel measurement technique is employed to examine the gate leakage currents of the MOSFETs.

An investigation of instability and charge motion in metal-silicon oxide-silicon structures

The results of a detailed study of the charge motion and instability in thermally grown, undoped silicon dioxide films at high electric fields and elevated temperatures are presented. The transient behavior of the charge motion in the oxide is analyzed and a model proposed to explain the observations. It is shown that the instability consists of the motion of positively charged ions and that interface trapping effects play a significant role in determining the transient behavior. Detailed consideration is given to the nature of these trapping effects, and it is concluded that caution must be exercised in ascribing the activation energy measured for the instability to that for the true mobility of these ions in a bulk oxide. The effects of various ambient treatments on the instability are discussed, and conclusions are drawn concerning the physical and chemical nature of the observed instability.