Correlated diffusion of impurities and silicon in next-generation gate insulating film

在奈米电子学时代，了解先进积体电路制程中的矽扩散现象变得越来越重要。例如，控制源极和漏极区域中杂质的不希望的过度扩散、二氧化硅的形成机制等需要理解硅原子的行为。在本计画中，我们利用二次离子质谱（西姆斯）技术，以硅的两种稳定同位素（~ <28>3Si和~ 4Si<30>）为标记物，探讨硅在源漏区和二氧化物薄膜形成过程中的扩散和化学反应。我们已经特别集中在离子注入的硼杂质的扩散，其扩散的影响显着的二氧化硅和硅的界面处产生的SiO缺陷，并扩散到由硼杂质掺杂的硅的区域。从而解决了以往报道的硼扩散增强的难题，并成功地建立了一个理论模型来模拟和再现实验。该模型将有助于纳米硅工艺模拟器的开发。

Understanding of silicon diffusion in the course of the advanced IC processing is becoming increasingly important in the era of nanoelectroics. For example, control of unwanted over diffusion of impurities in source and drain regions, formation mechanisms of silicon dioxide, etc. requires understanding of behaviors of silicon atoms. Up to know such details have been neglected in the research despite of its importance.In this project, we have employed two stable isotopes of silicon (^<28>Si and ^<30>Si) as markers for the secondary ion mass spectroscopy (SIMS) measurement to probe the diffusion and chemical reaction of silicon in the process of formation of source-drain regions and of thin film dioxide. We have concentrated especially on the diffusion of ion-implanted boron impurities whose diffusions are affected significantly by SiO defects that are generated at the interface of silicon dioxide and silicon, and diffuse to the region of silicon doped by boron impurities. As a result we have resolved the puzzle of the enhanced boron diffusion reported previously and succeeded in construction of a theoretical model to simulate and reproduce experiments. Such model will be useful for the development of nanosilicon process simulators.