SIGE HBT THESIS

Therefore, it makes more sense to use the coupled segregation and diffusion model to extract the segregation coefficients from experiments with annealing time short enough to avoid stress relaxation. Weijun Luo for their kind help. Existing studies of P diffusion in strained-SiGe have been performed mostly using furnace annealing, mainly because of the availability of the tools, long anneal time and better temperature accuracy for diffusion study. P tends to segregate out of SiGe region, which happens simultaneously with diffusion. However, if the annealing time at the peak temperature is too short, there will not be sufficient time for diffusivity extraction at this specific temperature. The impact of carbon and Ge on P diffusion in strained SiGe: However, the strongest retardation is in C molar fraction range of 0.

The fitting parameter value was modified until a good match to the post-annealed SIMS profile was achieved. The above studies suggest that the diffusion mechanisms of B and P in Si may be similar, but they are different enough in strained-SiGe to cause the difference of carbon retardation effectiveness. Concentrations are in cm In this study, it is the phosphorus, carbon, silicon and germanium profiles which are obtained simultaneously for each sample. C under rapid thermal anneal conditions were studied quantitatively. In many process simulation tools, diffusion flux is well modelled, where segregation flux is not commonly included except at material interfaces. Howard Ho for facilitating the funding process from TI.

Base doping profile control for SiGe PNP HBTs – UBC Library Open Collections

Their insightful questions and constructive advice helped me a lot in improving my work. C and SIMS results to measure the carbon substitutionality, as discussed in 4. To analyze the thermal nitridation effect on P diffusion we can apply the point-defect assisted diffusion theory, as described in Ch. Cambridge Scientific Publishers Limited, Experimentally, if we examine the actual concentration profile of many diffused dopants, we find that the diffusion appears to be faster in the higher-concentration regions.

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C under rapid thermal anneal conditions were studied quantitatively. Materials in Electronics, vol.

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So far, there has been no systematic and quantitative study on the carbon retardation effect on P diffusion in SiGe, which is addressed in this work. The Ge dependence can be explained by the increasing contribution from vacancy-assisted mechanism for P diffusion in strained SiGe with the increasing Ge content.

Below is an example: This topic will be discussed in Chapter 6. Erik Haralson ; KTH. SIMS is based on the fact that charged atomic and molecular species are ejected from the surface of a sample under heavy particle bombardment. Proceedings of the Meeting,pp. Considering the relatively low concentration of carbon, gbt will treat Si and SiGe as the diffusion media material, as the role of carbon is to change the point-defect concentrations and stress in SiGe. Ed Myers and Mr.

However, carbon diffusion is retarded under the nitridation condition, as seen in the carbon rising edge at the depth below 40 nm and in the falling edge in the to nm depth range. When this method is extended from Si to SiGe, the situation has changed.

In a fully strained epitaxial layer, its in-plane lattice constant equals to that of the substrate. To observe the coupled diffusion segregation phenomena, we designed structures to let dopants diffuse and segregate across the graded SiGe jbt.

Same is true for vacancies. The P base profiles are simulated using the diffusion-segregation model and the diffusion only model for comparison.

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: SIGE HBT

theiss Usually, this force is so called the driving force for diffusion. For diffusion study, the depth profiling of an interested element is crucial. All the analysis of these characterizations, theoretical derivations, modeling and simulations were conducted by the author.

sige hbt thesis

This model is generic to coupled diffusion and segregation in inhomogeneous alloys, and provides a new approach in segregation coefficient extraction, which is especially helpful for heterostructures with lattice mismatch strains.

The minimum formation energy of an interstitial carbon in split configuration is 4. Ge18C tends to relax the most as it has the highest Ge sie in this hbf and no carbon. For HBT device performance, depending on the applications, two figures of merits are important. The carbon profiles in all other diffusion structures are similar, and are not shown for clarity.

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website. In a piece of material, there are numerous atoms whose kinetic energies are sge equal and follow a natural and dynamic distribution.

In this study, we re-derived a diffusion-segregation model clearly showing the diffusion and segregation fluxes, and performed P segregation experiments at SiGe slopes to verify hbr model. This trend is similar to the case of Si1-yCy. These two types of point defects are called native point defects, or intrinsic point defects.

sige hbt thesis