Dopant behavior in complex semiconductor systems

textAs the size of modern transistors is continuously scaled down, challenges rise in almost every component of a silicon device. Formation of ultra shallow junction (USJ) with high activation level is particularly important for suppressing short channel effects. However, the formation of low resistance USJ is made difficult by dopant Transient Enhanced Diffusion (TED) and clustering-induced deactivation. In this work, we proposed a novel point defect engineering solution to address the arsenic TED challenge. By overlapping arsenic doped region with silicon interstitials and vacancies, we observed enhanced and retarded arsenic diffusion upon anneal, respectively. We explain this phenomenon by arsenic interstitial diffusion mechanism. In addition, we implemented this interstitial-based mechanism into a kinetic Monte Carlo (kMC) simulator. The key role of interstitials in arsenic TED is confirmed. And we demonstrated that the simulator has an improved prediction capability for arsenic TED and deactivation. As a long time unsolved process challenge, arsenic segregation at SiO₂/Si interface was investigated using density functional theory (DFT) calculation. The segregation-induced arsenic dose loss not only increases resistance but also may induce interface states. We identified three arsenic complex configurations, [chemical formula] , [chemical formula] and [chemical formula], which are highly stabilized at SiO₂/Si interface due to the unique local bonding environments. Therefore, they could contribute to arsenic segregation as both initial stage precursors and dopant trapping sites. Our calculation indicates that arsenic atoms trapped in such interface complexes are electrically inactive. Finally, the formation and evolution dynamics of these interface arsenic-defect complexes are discussed and kMC models are constructed to describe the segregation effects. A potential problem for the p-type USJ formation is the recently found transient fast boron diffusion during solid phase epitaxial regrowth process. Using DFT calculations and molecular dynamics simulation, we identified an interstitial-based mechanism of fast boron diffusion in amorphous silicon. The activation energy for this diffusion mechanism is in good agreement with experimental results. In addition, this mechanism is consistent with the experimentally reported transient and concentration-dependent features of boron diffusion in amorphous silicon.Electrical and Computer Engineerin

When and Where: Predicting Human Movements Based on Social Spatial-Temporal Events

Predicting both the time and the location of human movements is valuable but challenging for a variety of applications. To address this problem, we propose an approach considering both the periodicity and the sociality of human movements. We first define a new concept, Social Spatial-Temporal Event (SSTE), to represent social interactions among people. For the time prediction, we characterise the temporal dynamics of SSTEs with an ARMA (AutoRegressive Moving Average) model. To dynamically capture the SSTE kinetics, we propose a Kalman Filter based learning algorithm to learn and incrementally update the ARMA model as a new observation becomes available. For the location prediction, we propose a ranking model where the periodicity and the sociality of human movements are simultaneously taken into consideration for improving the prediction accuracy. Extensive experiments conducted on real data sets validate our proposed approach

大型国企一线工人的心理需要状况及其与离职倾向、工作满意度的关系——以A国企为例

Based on Maslow’s hierarchy of needs theory, the article to investigate the worker’s psychological needs in a large state-owned enterprises. It analyzed workers of different ages , different education level, and their differences in psychological needs structure characteristics and strength.The subjective turnover intention and job satisfaction are correlative of psychological needs. The article proposed the suitable management strategies of the worker’s psychological needs.本研究依据需要层次理论，以国业有企A为例，对一线工人的心理需要进行调查研究，分析了不同年龄、不同受教育程度的工人，心理需要结构特征和强度的差异，并对工人的离职倾向、工作满意度与不同需要层次的关系进行相关研究。提出了适应工人不同心理需要特征的管理策略建议

Dynamic Furnace Temperature Setting Research on Combustion System of Rolling Mill Reheating Furnace

AbstractThe setting of furnace temperature in combustion system of reheating furnace at rolling mill is an important parameter in the production process. Variety of some factors such as furnace heating capacity, steel thermal stress, production rhythm etc. directly affects the setting of furnace temperature, it is an industry problem. This article analysis about how the above mentioned factors affect the furnace temperature setting, and mainly focus on dynamic setting strategy of furnace temperature so as to fit fluctuation of production rhythm through theoretical analysis on the energy balance of billet heat transfer in the furnace. This strategy has been verified by production and experiment, and matches with the related data