If thin films are prepared from a sputtering target that contains three different oxides in same weight percentage (33.3%)..... what might be the XRD of the film look like??
Will it contain all three oxides phases or it will be a amorphous??
And why???
It's worth nothing that sputtering will be able to ablate the mixture target but with three different oxide ablation rate but deposit different ratios films which called the stoichiometry failure. In addition to the three oxides phases you would find many possible oxides phases of the target contents especially the low valence. However, such defects could be optimized through using sufficient oxygen gas pressure, RF power and Ar pressure.
If you perform deposition without temperature, for sure the resultant oxide will be amorphous. Deposition at hot substrate or post thermal treatment will provide crystalline oxides, in your case, with more than one phase. Deposition with target contend of In2O3 and SnO2, could results at single fase of ITO, or ITO and SnO2 dependendo on deposition ratio, temperature and partial oxigen pressure. I belive that add ZnO will result in the probability to get, at same time: IZO, ITO, SnO2, In2O3 and ZnO. Because, in general, depositon temperatures isn't behalf the ionic difusion.
Zn-Sn-In-O based compound may form with variable concentrations of individual elements which certainly depend on the power of the RF used, Ar:O2 ratios. However, individual phases of SnO2, ZnO or In2O3 are also expected. If the O2 flow is less then SnO (i.e. less oxidation state of metal element is also expected) !
Zn-Sn-In-O based compound may form with variable concentrations of individual elements which certainly depend on the power of the RF used, Ar:O2 ratios. However, individual phases of SnO2, ZnO or In2O3 are also expected. If the O2 flow is less then SnO (i.e. less oxidation state of metal element is also expected) !
This question has no simple answer. Depending on deposition conditions (deposition rate, substrate temperature, including effective heating by ion bombardment, and oxygen partial pressure) and composition of the deposited material one can get amorphous film, polycrystalline film (single-phase or with different phases present), or oriented ("epitaxial") film (again, both single-phase and multi-phase film can be obtained). The observed phases vary from single oxides to mixed oxides, and even chimera phases (thermodynamically not stable) can be grown by sputter deposition on "cold" substrates.
In general, lowering deposition temperature promotes formation of amorphous films and single-oxide phases; increasing deposition temperature - oriented films and stable mixed-oxide phases; mixing of the elements is promoted (to some extents) by ion bombardment when substrate is brought closer to the target, and by high deposition rate. Oxygen partial pressure influences all properties of the film, and this influence may be very different. One should compare thermodynamic stability of different possible phases at certain oxygen partial pressure and choose the conditions that would favor the desired phase.
Dear Arindam,
The colleagues gave satisfactory answers to the questions. I would like to stress that the ratio of the three oxides will not be 1:1:1 as the ejection rates and the deposition rates are not equal. Therefore i would propose that measure the composition after deposition using XRD.
Best wishes
hi
Will it contain all three oxides phases or it will be a amorphous??
actually it may contains all phases and gives no peak in the diffraction patterns. so simply do XRD and you will see if the composition is amorphous or not.
The amorphous nature of the film indicates that this film has glass forming ability. This behavior could be attributed to a number of reasons. The first reason is the cooling rate. As all films were taken directly from the hot plate at 723 K, for example, to room temperature which gives a cooling rate, if we assumed the cooling takes 1 min, 723 KS-1. Such cooling rate may be high enough to give the film materials no chance to form crystalline nature, like in the case of La-Co mixed oxides. Such cooling rate has been observed in more complicated systems like Pb10Cu30Ni10P20, Zr41.2Ti13.8Cu12.5Ni10Be22.5 where amorphous phases were observed at cooling rates of 10 KS-1 and 1 KS-1, respectively. Another reason is the thermodynamic state function, enthalpy, ∆H, and the entropy, ∆S. Increasing the entropy or lowering the enthalby decreases the homogenous rate of nucleation rate and crystallization growth rate which enhance the amorphousity of the formed films
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