A Comparison of the Semiconducting Properties of Thin Films of Silicon on Sapphire and Spinel

In Fig. 6, Eg (opt) vs. CH~% are shown for undoped, P-type and N-type a-SiC:H. The Eg (opt) increases monotonically with increasing CH4% in all cases. But the rates of increase in Eg (opt) with increasing CH4% are different. The order of the rate is as follows: Undoped is the first, N-type the second, and P-type the third. The rate of undoped and N-type are nearly the same. It seems that there is a small shoulder in the curves of Eg (opt) of all the a-SiC: H at nearly 40% of CH4. The Eg (opt) shrinkage was observed only for P-type a-SiC:H with increasing dopant concentration. Summary and DiscussionWe found the clear maxima in ~D in the P-type glowdischarged a-Si: H films. The origin of this peak has not yet been clarified. But it is worthy of note that the dopant and hydrogen form dopant-hydrogen complexes (6). The shoulder of the ~ph of P-type a-SiC: H reported by Tawada et al.(3) seems to be located right above the ~D peak, and the recovery of the cph by boron doping, as reported in the literature, seems to be related to th ~D peak. The peak appears to result from the two curves. One is the up slope curve and the other is the down slope one. It is inferred that the increase in ~D in the up slope curve is caused by more incorporation of boron which becomes electrically active in accordance with the increase in the flow rate of CH4, while the decrease in ~D in the range over 30% of the flow rate of CH4 is concerned v~ith the degradation of quality of the a-SiC:H and increase in Eg (opt) by the higher concentration of carbon. Studies on the origin of the peak in ~'D for the P-type a-SiC:H is presently being planned.ABSTRACT Epitaxial growth of single-crystal Si films has been realized on the (100), (110), and (111) crystallographic planes of yttria-stabilized, cubic zirconia single crystals. The Si films were grown by chemical vapor deposition, using the pyrolysis of Sill4 at temperatures in the range 950 ~ 1075~ and at deposition rates of 0.08-1.2 ~m/min. A predeposition annealing procedure has been developed, resulting in a quasi-stable, oxygen-deficient zirconia surface. A model is presented to explain the dependence of oxygen kinetics in cubic zirconia on temperature and yttria content. The heteroepitaxial Si films have been characterized by optical and scanning electron microscopies, reflection electron diffraction, x-ray diffraction, Rutherford backscattering and channeling, and surface electrical conductivity and Hall effect measurements. Several 0.4-0.5 ~m thick (100)-and (110)-oriented Si films on cubic zirconia were found to be of higher crystal quality than commercial (100) Si on sapphire films of similar thickness.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 144.122.201.150 Downloaded on 2016-03-28 to IP

Section: Si Film Characterization: Electrical Properties--thementioning

confidence: 99%

Si on Cubic Zirconia

Manasevit

Golecki

Moudy

et al. 1983

“…Key words: thin films, dielectric amorphous alumina, Ta-doping, Poole-Freukel electrical conduction, (ii). In addition, the introduction of impurity during film formation may also favor the growth of amorphous films due to an increase in configurational entropy (12), and/or due to the impurity-induced change of film nucleation and growth behavior (13). It may therefore be possible to form amorphous CVD A1203 films at relatively high temperatures by impurity doping.…”

Section: Amorphous Cvdmentioning

confidence: 99%

The Preparation and Properties of (111)Si Films Grown on Sapphire by the SiH4 ‐ H 2 Process

Manasevit

Erdmann

Thorsen

1976

An experimental study of the effects of various parameters on the properties of (111) and (100)Si films grown on sapphire false(α‐Al2O3false) by the SiH4 pyrolysis CVD method has been carried out. The following were examined: autodoping, growth temperature and growth rate, As‐doped n‐type films, p‐type films doped with B, properties as a function of film thickness, and the effect of reactor configuration. It was determined that at growth rates of ∼2–6 μm/min in a vertical reactor n‐type (111) Si films grown at temperatures of 1050°–1100°C on Al2O3 substrates oriented near the (112̅0) plane are electrically superior to those grown on false(011̅2false)Al2O3 and false(101̅4false)Al2O3 over the temperature range 950°–1100°C. Films with electron mobilities as high as 600–700 cm2/V‐sec for carrier concentrations of 1016–1017 cm−3 were obtained. P‐type Si films grown using B2H6 as the dopant source were also electrically better on ∼false(11̅20false)Al2O3 [(111)Si‐growth] than on false(011̅2false)Al2O3 [(100)Si growth], Hall mobilities being ∼2–3 times larger for hole concentrations 1016– 1017 cm−3. A comparison of film properties of n‐type films as a function of thickness indicated both the (100) and (111)Si films behave essentially the same way, i.e., the average mobilities show a steady decrease with decreasing film thickness. These studies revealed the strong interrelationships that exist among the various parameters involved in optimizing Si growth on insulators and indicated that growth conditions (i) must be optimized for the particular substrate orientation chosen; (ii) differ for those substrate orientations which lead to the same Si orientation; (iii) are dependent on reactor geometry; and (iv) should be optimized for the particular film thickness desired.

“…The experimental observation that this thickness is somewhat less with sapphire than with spinel can be explained by the different nucleation behavior of the two materials. The average thickness which is necessary to cover the substrate completely is smaller in the case of sapphire (15,17), so that the thickness of the intermediate layer is also smaller. It seems that the intermediate layer matches the differences between substrate and silicon lattice.…”

Section: Analysis Os the Intermediate ~Ayermsecondary Ion Mass Spectr...mentioning

confidence: 99%

An Optically Effective Intermediate Layer Between Epitaxial Silicon and Spinel or Sapphire

Kühl

Schlötterer

Schwidefsky

1976

The existence of an optically effective intermediate layer between epitaxial silicon and spinel or sapphire has been proved. By measuring the optical and geometric thickness of the films as a function of film thickness a difference in the thickness values was found which could be interpreted as the thickness of an intermediate layer. This layer was also measured directly with a stylus tracer yielding a thickness of about 40 nm. Reflection electron diffraction and secondary ion mass spectroscopy were performed. A growth model for the silicon films is proposed which assumes that aluminum silicates will be formed due to reactions with the substrate as long as the substrate surface is uncovered. Despite or possibly because of this existing intermediate layer good epitaxial silicon films are obtained.