Plasma enhancement

PECVD. See Plasma-enhanced chemical vapor deposition. 

Dielectric Film Deposition. Dielectric films are found in all VLSI circuits to provide insulation between conducting layers, as diffusion and ion implantation (qv) masks, for diffusion from doped oxides, to cap doped films to prevent outdiffusion, and for passivating devices as a measure of protection against external contamination, moisture, and scratches. Properties that define the nature and function of dielectric films are the dielectric constant, the process temperature, and specific fabrication characteristics such as step coverage, gap-filling capabihties, density stress, contamination, thickness uniformity, deposition rate, and moisture resistance (2). Several processes are used to deposit dielectric films including atmospheric pressure CVD (APCVD), low pressure CVD (LPCVD), or plasma-enhanced CVD (PECVD) (see Plasma technology). 

There are two types of deposited films known as siUcon nitride. One is deposited via plasma-enhanced CVD at temperatures <350° C (18). In this process silane and ammonia react in an argon plasma to form siUcon imide [14515-04-9] SiNH. 

J. E. Griffiths, ed.. Monitoring and Control of Plasma-Enhanced Processing of Semiconductors, SPIE-International Society for Optical Engineering,... 

Dielectric Deposition Systems. The most common techniques used for dielectric deposition include chemical vapor deposition (CVD), sputtering, and spin-on films. In a CVD system thermal or plasma energy is used to decompose source molecules on the semiconductor surface (189). In plasma-enhanced CVD (PECVD), typical source gases include silane, SiH, and nitrous oxide, N2O, for deposition of siUcon nitride. The most common CVD films used are siUcon dioxide, siUcon nitride, and siUcon oxynitrides. 

Plasmas can be used in CVD reactors to activate and partially decompose the precursor species and perhaps form new chemical species. This allows deposition at a temperature lower than thermal CVD. The process is called plasma-enhanced CVD (PECVD) (12). The plasmas are generated by direct-current, radio-frequency (r-f), or electron-cyclotron-resonance (ECR) techniques. Eigure 15 shows a parallel-plate CVD reactor that uses r-f power to generate the plasma. This type of PECVD reactor is in common use in the semiconductor industry to deposit siUcon nitride, Si N and glass (PSG) encapsulating layers a few micrometers-thick at deposition rates of 5—100 nm /min. 

In PECVD, the plasma generation region may be in the deposition chamber or precede the deposition chamber in the gas flow system. The latter configuration is called remote plasma-enhanced CVD (RPECVD). In either case, the purpose of the plasma is to give activation and partial reaction/reduction of the chemical precursor vapors so that the substrate temperature can be lowered and still obtain deposit of the same quaUty. 

Many materials have been deposited by PECVD. Typically, the use of a plasma allows equivalent-quaUty films to be deposited at temperatures several hundred degrees centigrade lower than those needed for thermal CVD techniques. Often, the plasma-enhanced techniques give amorphous films and films containing incompletely decomposed precursor species such as amorphous siUcon (i -Si H) and amorphous boron (i -B H). 

Hoffman, D. M., et al., Plasma-Enhanced CVD of Silicon Nitride Films from a Metallo-Organic Precursor, J. Mater. Res., 9(12) 3019-3021 (1994)... 

Thermal CVD, reviewed above, relies on thermal energy to activate the reaction, and deposition temperatures are usually high. In plasma CVD, also known as plasma-enhanced CVD (PECV) or plasma-assisted CVD (PACVD), the reaction is activated by a plasma and the deposition temperature is substantially lower. Plasma CVD combines a chemical and a physical process and may be said to bridge the gap between CVD andPVD. In this respect, itis similar to PVD processes operating in a chemical environment, such as reactive sputtering (see Appendix). 

Kember, P. N., and Astell-Burt, P. J., Plasma-Enhanced CVD of Tungsten and Tungsten Silicide, Vide, Couche Minces, 42(236) 167-173 (Mar.-Apr., 1987)... 

Plasma-enhanced deposition from silane (see below). 

Reif, R., Low Temperature Silicon Epitaxy by Plasma Enhanced CVD, Proc. 5th European Conf. on CVD, (J. Carlsson and J. Lindstrom, eds.), pp. 13-19, Univ. ofUppsala, Sweden (1985)... 

Marks, J., Witty, D., Short, A., Laford, W., and Nguyen, B., Properties of High Quality Nitride Films by Plasma Enhanced Chemical Vapor Deposition, Proc. 11th. Int. Conf. on CVD, (K. Spear and G. Cullen, eds.), pp. 368-373, Electrochem. Soc., Pennington, NJ 08534 (1990)... 

Tsu, D. V., and Lucovsky, G., Silicon Nitride and Silicon Diimide Grown by Remote Plasma Enhanced Chemical Vapor Deposition, J. Vac. Set. Technol. A, 4(3-1 ) 480-485 (May-June 1986)... 

In some cases, the deposition rate can be increased by the action of a plasma in a process known as activated reactive evaporation (ARE). PI The plasma enhances the reactions and modifies the growth kinetics of the deposit. 

DEC coating was first prepared by Aisenberg and Chabot using ion beam deposition in 1971 [2]. At present, PVD, such as ion beam deposition, sputtering deposition, cathodic vacuum arc deposition, pulsed laser deposition, and CVD, like plasma enhanced chemical vapor deposition are the most popular methods to be selected to fabricate DEC coatings. 

At the end of last century, a near frictionless carbon (NFC) coating was reported, which is practically hydrogen contained DLC film grown on steel and sapphire substrates using a plasma enhanced chemical vapor deposition (PECVD) system [50]. By using a ball on a disk tribo-meter, a super low friction coefficient of 0.001-0.003 between the films coated on both the ball and the disk was achieved [50]. A mechanistic model was proposed that carbon atoms on the surface are partially di-hydrogenated, resulting in the chemical inertness of the surface. Consequently, adhesive interaction becomes weak and super low friction is achieved [22],... 

Ramsey, M. E., Poindexter, E., Pelt, J. S., Marin, J., and Durbin, S. M., Hydrophobic CNx Thin Film Growth by Inductively-coupled RF Plasma Enhanced Pulsed Laser Deposition, Thin Solid Films, Vol. 360, No. 1-2,2000, pp. 82-88. 

Prakash, G. V., Cazzanell, M., Gaburro, Z., Pavesi, L., lacona, F., Franzo, G. and Priolo, F. (2002) Nonlinear optical properties of silicon nanocrystals grown by plasma-enhanced chemical vapor deposition. /. Appl. Phys., 91, 4607 610. 

The radio-frequency glow-discharge method [30-34] has been the most used method in the study of a-C H films. In this chapter, it is referred to as RFPECVD (radio frequency plasma enhanced chemical vapor deposition). Film deposition by RFPECVD is usually performed in a parallel-plate reactor, as shown in Figure 1. The plasma discharge is established between an RF-powered electrode and the other one, which is maintained at ground potential. The hydrocarbon gas or vapor is fed at a controlled flow to the reactor, which is previously evacuated to background pressures below lO"" Torr. The RF power is fed to the substrate electrode... 

The compound truw-perfluoro-l-methyl-1-propenylsilver has been shown to be tetrameric, [CF3CF=C(CF3)Ag]4, and it is a suitable precursor to prepare pure silver films by plasma-enhanced CVD, or to deposit silver films under MOCVD conditions. 

Plasma Enhanced Chemical Vapour Deposition (PECVD) Chemical vapour deposition (CVD) reactions commonly occur at high temperatures (Table II). The use of a plasma to generate chemically reactive species in conjunction with CVD overcomes one of the most common... 

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