Deposition parameters

Chemical Inhomogenities or Compositional Separation. Compositional separation at the grain boundaries influences the magnetic interactions of the individual grains. Deposition parameters such as temperature, substrate material, and the use of a seed layer play an important role. 

The optoelectronic properties of the i -Si H films depend on many deposition parameters such as the pressure of the gas, flow rate, substrate temperature, power dissipation in the plasma, excitation frequency, anode—cathode distance, gas composition, and electrode configuration. Deposition conditions that are generally employed to produce device-quahty hydrogenated amorphous Si (i -SiH) are as follows gas composition = 100% SiH flow rate is high, --- dO cm pressure is low, 26—80 Pa (200—600 mtorr) deposition temperature = 250° C radio-frequency power is low, <25 mW/cm and the anode—cathode distance is 1-4 cm. 

CVD reactions are most often produced at ambient pressure in a freely flowing system. The gas flow, mixing, and stratification in the reactor chamber can be important to the deposition process. CVD can also be performed at low pressures (LPCVD) and in ultrahigh vacuum (UHVCVD) where the gas flow is molecular. The gas flow in a CVD reactor is very sensitive to reactor design, fixturing, substrate geometry, and the number of substrates in the reactor, ie, reactor loading. Flow uniformity is a particulady important deposition parameter in VPE and MOCVD. 

In electro deposition, the film stresses can vary with deposition parameters and be regulated by controlling the deposition parameters and the use of addition agents in the bath. 

Trajectory models require spatiaUy and temporaUy resolved wind fields, mixing-height fields, deposition parameters, and data on the spatial distribution of emissions. Lagrangian trajectory models assume that vertical wind shear and horizontal diffusion are negligible. Other limitations of trajectory and Eulerian models have been discussed (30). 

The electrodeposition of Cr in acidic chloroaluminates was investigated in [24]. The authors report that the Cr content in the AlCr deposit can vary from 0 to 94 mol %, depending on the deposition parameters. The deposit consists both of Cr-rich and Al-rich solid solutions as well as intermetallic compounds. An interesting feature of these deposits is their high-temperature oxidation resistance, the layers seeming to withstand temperatures of up to 800 °C, so coatings with such an alloy could have interesting applications. 

Mobilities up to 1.5 cm2 V-1 s 1 have been obtained for films deposited on hcale substrates [94—96]. As in the case of oligothiophenes, this has been attributed to a highly ordered morphology, close to that of a single crystal [94]. However, high values are only obtained under very acute deposition parameters (in particular an opti... 

It is possible to control the nature of a CVD structure by the proper manipulation of the deposition parameters such as temperature, pressure, supersaturation, and the selection of the CVD reaction. 

At higher pressure (i.e., atmospheric), the reactant gas must be diluted with an non-reactive gas, such as hydrogen or argon, to prevent vapor-phase precipitation, while generally no dilution is necessary at low pressure. However, atmospheric-pressure reactors are usually simpler and cheaper, and, with proper control of the deposition parameters, satisfactory deposits may be obtained. 

The deposition of graphite is also obtained by plasma CVD, with the following deposition parameters ]... 

The substrate temperature should be kept between 800 and 1000°C and cooling may be necessary. Gas composition and other deposition parameters are similar to those used in a microwave-plasma system. Deposition rate is low, reported as 0.5 to 1 im/h. 

The friction coefficient of Sample 2 is quite different from the other samples this can be attributed to the surface difference. The previous research shows that the friction coefficient of DLC is related to the deposition parameter [29]. In this study, in order to evaluate the surface properties in the same condition, we designed Layer A as the outermost layer for all the multilayer samples. Among all the samples, only the surface of Sample 2 is from Layer B. 

The gas flow rate is usually presented as a deposition parameter however, it is much more instructive to report the gas residence time [6], which is determined from the flow rate and the geometry of the system. The residence time is a measure of the probability of a molecule to be incorporated into the film. The gas depletion, which is determined by the residence time, is a critical parameter for deposition. At high flow rates, and thus low residence times and low depletion [303], the deposition rate is increased [357, 365] (see Figure 39) and better film quality is obtained, as is deduced from low microstructure parameter values [366],... 

The substrate temperature is a very important deposition parameter, as it directly affects the kinetics of ad- and desorption of growth precursors, surface diffusion, and incorporation. Actual substrate temperatures may differ from substrate heater setpoints. Calibration of temperature readings is needed, so as to report the correct substrate temperature. 

A change of excitation frequency prompts for optimization of other deposition parameters, such as pressure, power, and geometry. Chatham and Bhat have shown that the maximum of SiH emission at 414 nm is shifted towards lower pressure... 

In Table I are shown representative data concerning plasma deposition of a-C(N) H films, produced by different methods and under different gaseous mixtures and deposition parameters. In this table are displayed data on chemical composition (maximum N content, and range of variation of H content), deposition details (deposition pressure, self-bias, and atmosphere composition), and the method used for chemical composition determination. 

Chemical Composition and Deposition Parameters of Plasma-Deposited a-C(N ) H Films... 

Many researchers have found that differences in film deposition techniques and deposition parameters profoundly influence the oxidation and stability of MO layers. For example, increases of Ar pressure and bias voltage, leading to more porous structures, result in easier oxidation and quicker changes in aging tests [168-172], Such films are particularly corrosion-prone. 

Semin D.J., Rowlen K.L., Influence of vapor-deposition parameters on SERS active Ag film morphology and optical-properties, Anat. Chem. 1994 66 4324-4331. 

---