We have used both electrical and optical characterization methods to study the effect of carbon on the valence band offset of compressively strained Si1-x-yGexCy / Si (100) heterojunctions grown by Rapid Thermal Chemical Vapor Deposition (RTCVD) with substitutional C levels from 0% to 2.5%. Our work indicates that the change in the bandgap of Si1-x-yGexCy as carbon is added is entirely accommod...

The performance and material quality requirements of thin film a-Si/c-Si1-xGex/Si heterojunction solar cells are investigated by modeling and simulation. The effects of Ge content, Si1-xGex thickness, Si1-xGex lifetime and a-Si/c-Si1-xGex interfacial quality have been studied. The simulations predict that Si1-xGex based thin film solar cells provide a significant increase in solar cell output c...

Strong boron segregation to polycrystalline Si1 x yGexCy alloys from Si has previously been reported [MRS Symp. Proc. 669 (2001) J6.9]. In this study, we investigate potential mechanisms for this effect. We find that comparable segregation also occurs in both polycrystalline Si1 yCy and single-crystal Si1 x yGexCy, indicating neither Ge nor grain boundary effects are needed for it to occur. In ...

Boron penetration through thin gate oxides in p-channel MOSFETs with heavily boron-doped gates causes undesirable positive threshold voltage shifts. P-channel MOSFETs with polycrystalline Si1 x yGexCy gate layers at the gate-oxide interface show substantially reduced boron penetration and increased threshold voltage stability compared to devices with all poly Si gates or with poly Si1 xGex gate...

The effects of three different feeding systems on beef cattle production performance, rumen fermentation, and rumen digesta particle structure were investigated by using 18 Limousin (steers) with a similar body weight (575±10 kg) in a 80-d experiment. The animals were equally and randomly divided into three treatment groups, namely, total mixed ration group (cattle fed TMR), SI1 group (cattle f...

Formation of Kirkendall voids is demonstrated in the Ge underlayer of reverse step graded Si1−xGex/Ge buffer layers grown on Si(001) using reduced pressure chemical vapour deposition (RP-CVD). This phenomenon is seen when the constant composition Si1−xGex layer is grown at high temperatures and for x„0.7. The density and size of the spherical voids can be tuned by changing Ge content in the S...

The structure of the Sn1 xGex random alloys is studied using density functional theory and the coherent potential approximation. We report on the deviation of the Sn1 xGex alloys from Vegard’s law, addressing their full compositional range. The findings are compared to the related Si1 xGex alloys and to experimental results. Interestingly, the deviation from Vegard’s law is quantitatively and q...

Let n be a natural number such that n ≥ 2, and let a1, . . . an be positive numbers. Considering the notations Si1... ik = ai1 + · · ·+ aik , S = a1 + · · ·+ an, we prove certain inequalities connected to conjugate sums of the form: ∑ 1≤i1<···<ik≤n Si1... ik S − Si1... ik Then provided that 1 ≤ k ≤ n − 1 we give certain lower estimates for expressions of the above form, that extend some cyclic ...

In this work, for the first time, the valence band offset, ∆EV, between strained Si and strained Si1-yGey on relaxed Si1-xGex, has been measured using a combination of experimentation and modeling. Such structures have been shown to offer large mobility enhancements for both electrons and holes, and knowledge of the band parameters is critical in order to optimize and predict device behavior [1...

It has been reported that boron segregates to single-crystal Si1−xGex layers from silicon during thermal anneals. In this work, we find that boron segregates even more strongly into single-crystal Si1−x−yGexCy, as has been previously reported for polycrystalline films. This effect is also observed in single-crystal Si1−yCy. Segregation coefficients range from 1.7 to 2.9 for annealing temperatur...