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- Christensen, JS, et al.
(författare)
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Diffusion of phosphorus in relaxed Si1-xGex films and strained Si/Si1-xGex heterostructures
- 2003
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 94:10, s. 6533-6540
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Tidskriftsartikel (refereegranskat)abstract
- Phosphorus diffusion has been studied in relaxed Si1-xGex samples (x=0.11 and 0.19) and strained Si/Si1-xGex/Si heterostructures (x=0.08, 0.13, and 0.18). The diffusivity of P is found to increase with increasing Ge content, while the influence of compressive strain results in a decrease in diffusivity as compared to that in relaxed material. The effect of strain is found to be equivalent to an apparent activation energy of -13 eV per unit strain, where the negative sign indicates that the P diffusion is mediated by interstitials in Si1-xGex (x<0.20). This conclusion is also supported by an experiment utilizing injection of Si self-interstitials, which results in an enhanced P diffusion in strained Si1-xGex. Further, P is found to segregate into Si across Si/Si1-xGex interfaces and the segregation coefficient increases with increasing Ge concentration.
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| 2. |
- Christensen, JS, et al.
(författare)
-
Phosphorus and boron diffusion in silicon under equilibrium conditions
- 2003
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 82:14, s. 2254-2256
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Tidskriftsartikel (refereegranskat)abstract
- The intrinsic diffusion of phosphorus and boron in high-purity epitaxial silicon films has been studied. Phosphorus diffusion in a wide temperature range (810 to 1100 degreesC) revealed diffusion coefficients with an Arrhenius behavior exhibiting an activation energy of 2.74+/-0.07 eV and a pre-exponential factor of (8+/-5)x10(-4) cm(2)/s. In the temperature range of 810 to 1050 degreesC, boron was found to diffuse with an activation energy of 3.12+/-0.04 eV and a pre-exponential factor of 0.06+/-0.02 cm(2)/s. These results differ from those of many previous studies, but this deviation may to a large extent be attributed to slow transients before equilibrium concentrations of point defects are established at temperatures below similar to1000 degreesC. Despite a similar diffusion mechanism mediated by Si self-interstitials, P exhibits a lower activation energy than B because of stronger bonding to the Si self-interstitial.
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