Considering the fact that the solid state diffusion is microscopically the random jump of atoms, this force may represent the spontaneous tendency of the atoms to disperse as a consequence of the Second Law of thermodynamics and the hunt for maximum entropy. Showing result 1 – 5 of 7 swedish dissertations containing the words sige hbt. For example, the atomic theory was established about one century ago and the general theory of relativity was published years ago, and they fundamentally changed our view of nature and universe. Fundamentals, Practice and Modeling. I would like to thank our collaborators at Texas Instruments TI: The sputter rate was calibrated by a stylus profilometer measurement of the sputtered carter depth and corrected on a point-by-point basis. The diagonal line represents the condition of fully substitutional incorporation i.
For p-type dopants, the effect is similar while all the charge states are just reversed. This uncertainty was taken into account in our simulations. Experimentally, the author designed all the sample structures and annealing conditions, prepared samples for secondary ion mass spectrometer SIMS. The effectiveness of the thermal nitridation method was studied based on these experiments. Mikroelektronik och informationsteknik Author: Since dopant diffusion relies on the help of point defects, we can control dopant diffusion by disturbing point defect concentrations. The theoretical derivations of coupled diffusion and segregation model of this work is generic to all inhomogenous solid solutions, and the experiments and model calibration are specifically relevant to PNP SiGe HBTs.
Historically, 74 the influence of thermal nitridation on point defects was observed indirectly by the growth or shrinkage of stacking faults and dopant diffusion , as the point defect concentrations are too low to be measured directly. Given some time, these atoms will 12 relocate themselves and find new positions. For example, the atomic layer deposition ALD developed recently is such a technique for this purpose .
It is therefore important to use the coupled diffusion-segregation model in the base doping and Ge profile design. The early studies of thermal nitridation mainly focused on how to produce high-quality thermal silicon nitride films , , .
The thermal budgets of the sihe were selected to avoid strain relaxation. Therefore we can only estimate the strain compensation effect, commonly expressed as a change in the diffusion activation energy, based thhesis previous studies on strain impact on dopant diffusion in strained-SiGe and relaxed-SiGe structures . A higher difference in Ge content results in a larger mismatch strain, thus a smaller critical thickness.
Many phenomena can happen with diffusion such as grain growth, phase change, segregation, etc. During direct nitridation where bare silicon wafers were annealed in ammonia, phosphorus and boron diffusion was retarded while antimony diffusion was enhanced.
It should be noted that carbon concentrations measured from SIMS are total carbon concentrations regardless of the carbon positions in the lattice.
Base doping profile control for SiGe PNP HBTs – UBC Library Open Collections
P tends to segregate out of SiGe region, which happens simultaneously with diffusion. Sge coupled diffusion and segregation model is re-derived skge on thermodynamic principles, where the contributions from diffusion and segregation to dopant flux are explicitly shown.
The human history of the utilization, renovation and invention of materials can be dated back beyond written records. If different materials are used for emitter and base regions, a heterojunction is created at the emitter-base junction and this BJT becomes an HBT. I would also like to thank Dr.
Search and download doctoral PHD dissertations from Sweden. Its application suge diffusion studies is an example. The P peak was designed to be inside the triangle SiGe region so that we could observe P segregation out from the Ge triangle to Si .
: SIGE HBT
In a reciprocal space map, the alignment of the diffraction spot from a SiGe layer with respect to the spot from the underlying Si substrate shows thesie this layer is fully strained i. The choice of SiGe layer thickness was based on two considerations: The epitaxial strained heterostructures provide ideal testbeds. The incorporation of alien neutral impurities is also possible to suppress dopant diffusion.
This indicated that the effects of thermal nitridation and carbon incorporation can both suppress boron diffusion and their impacts can be added to some extent, although the total effect is not simply the sum of the two effects. Figure reprinted from Ref. See yesterday’s most popular searches here. The RSMs were done on all structures and annealing conditions, and no strain relaxation was observed 41 for the structures after diffusion in this hbg.
In this case, coupled dopant diffusion and segregation models are required to describe the dopant profile evolution across the Ge concentration slopes.
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Newman and Wakefield concluded that, in bulk monocrystalline silicon, carbon resides predominantly on substitutional sites based on the observations that the diffusion coefficient and the activation energy of carbon are similar to those of the dopants . David Dixon and Prof.
In this study, it is the phosphorus, carbon, silicon sigd germanium profiles which are obtained simultaneously for each sample.
Guangrui Maggie Xia, for her guidance, patience and trust throughout my graduate journey. The goal of this chapter is to introduce them as a basis for more in-depth discussions in the following chapters.
To analyze the thermal nitridation effect on P diffusion we can apply the point-defect assisted diffusion theory, as described in Ch. Silicon-Germanium SiGe ; heterojunction bipolar transistor HBT ; low-frequency noise ; high-frequency noise ; harmonic distortion ; linearity ; device simulation ; collector profile ; epitaxial base integration ; radio frequency RF ; radio frequency inte ; Abstract: