Electron-cyclotron-resonance

Microwave discharges at pressures below 1 Pa witli low collision frequencies can be generated in tlie presence of a magnetic field B where tlie electrons rotate witli tlie electron cyclotron frequency. In a magnetic field of 875 G tlie rotational motion of tlie electrons is in resonance witli tlie microwaves of 2.45 GHz. In such low-pressure electron cyclotron resonance plasma sources collisions between tlie atoms, molecules and ions are reduced and the fonnation of unwanted particles in tlie plasma volume ( dusty plasma ) is largely avoided. 

The requirements of thin-film ferroelectrics are stoichiometry, phase formation, crystallization, and microstmctural development for the various device appHcations. As of this writing multimagnetron sputtering (MMS) (56), multiion beam-reactive sputter (MIBERS) deposition (57), uv-excimer laser ablation (58), and electron cyclotron resonance (ECR) plasma-assisted growth (59) are the latest ferroelectric thin-film growth processes to satisfy the requirements. 

RIE = reactive ion etching ECR = electron cyclotron resonance etching. 

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. 

A microwave plasma can also be produced by electron cyclotron resonance (ECR), through the proper combination of electric and magnetic fields.Cyclotron resonance is achieved when the frequency of the alternating electric field is made to match the natural frequency of the electrons orbiting the lines of force of the... 

Figure 5.19. Schematic of electron cyclotron resonance (ECR) microwave deposition apparatns.

This reaction was also used to deposit epitaxial silicon at the temperature range of 1000-1040°C, but the deposit was generally unsatisfactory and the reaction is no longer used for that purpose. However, if the reaction is enhanced with a plasma using electron cyclotron resonance (ECR), fluxes may be independently controlled and high-quality epitaxial silicon deposits are obtained at temperatures below 500°C.P 1... 

Like synthetic diamond, C-BN is normally obtained by high-pressure processing. Efforts to synthesize it by CVD at low pressure are promising. It is deposited in an electron-cyclotron-resonance (ECR) plasma from a mixture of BF3 and either ammonia or nitrogen at 675°C on an experimental basis.F l Like CVD diamond, it is also deposited by the hot-filament method using diborane and ammonia diluted with hydrogen at 800°C.P 1... 

However, the nitrogen molecule has afar greater bonding energy than ammonia and is more difficult to dissociate into free atomic nitrogen active species. Consequently, the deposition rate is extremely slow. This can be offset by plasma activation with high frequency (13.56 MHz) or electron cyclotron resonance (ECR) plasmasP Ef l and with micro-wave activation. 

Some of the most significant developments in the CVD of Si02 include experiments in plasma CVD at 350°C via electron cyclotron resonance (ECR) to gain improved control of the deposition rate and obtain a quality equivalent to that of the thermally grown oxide (see Ch. 5). Deposition from diacetoxyditertiarybutoxy silane at 450°C has also been shown to significantly improve the Si02 film properties. " ]... 

Characteristics of Tin Oxide Thin Films on a Poly Ethylene Terephthalate Substrate Prepared by Electron Cyclotron Resonance-Metal Organic Chemical Vapor Deposition... 

In further sections extensions or adaptations of the PECVD method will be presented, such as VHF PECVD [16], the chemical annealing or layer-by-layer technique [17], and modulation of the RF excitation frequency [18]. The HWCVD method [19] (the plasmaless method) will be described and compared with the PECVD methods. The last deposition method that is treated is expanding thermal plasma CVD (ETP CVD) [20, 21]. Other methods of deposition, such as remote-plasma CVD, and in particular electron cyclotron resonance CVD (ECR CVD), are not treated here, as to date these methods are difficult to scale up for industrial purposes. Details of these methods can be found in, e.g., Luft and Tsuo [6]. 

FIG. 3. Schematic of plasma deposition by electron cyclotron resonance with an RF-biased substrate (ECRRF). 

Electron current density (je), 22 243 in silicon-based semiconductors, 22 238 Electron cyclotron resonance (ECR),... 

Pearton J, Abernathy CR, Ren F, Lothian JR, Wisk PW, Katz A (1993) Dry and wet etching characteristics of InN, AIN, and GaN deposited by electron cyclotron resonance metalorganic molecular beam epitaxy. J Vac Sci Technol A 11 1772-1175... 

Geller, R. Electron Cyclotron Resonance Ion Sources and ECR Plasmas Institute of Physics Publishing Bristol, 1996. 

The thermal instability of Baj.xKxBiOj compounds makes it desirable to utilize low temperature deposition techniques. Use of a three cell evaporation source coupled with oxygen, ionized by an electron cyclotron resonance source and accelerated toward the... 

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