高迁移率Si/SiGe/SOI量子阱MOS器件载流子散射机理研究

As the feature size of integrated circuit technology steps into nano-scale, tranditional CMOS technology will meet severe challenges resulting from mobility degradation and high power density. High mobility device is the most important method to address these challenges. Among all high mobility devices, Si/SiGe/SOI quantum-well MOS device is one of the most effective solution for high hole mobility p-MOS device. This study will focus on fundamental problems of Si/SiGe/SOI quantum-well MOS device. Carrier scattering mechanism in SiGe channel will be deeply studied and influence of scattering mechanism on carrier mobility, such as phonon scattering, Coulomb scattering and alloy scattering, will be investigated. Meanwhile, the effects of key parameters of the device on carrier scattering and mobility, including SiGe thickness, Ge concentration, strain, Si cap thickness and gate dielectric, will be systematically studied. Through this study, carrier scattering mechanism of Si/SiGe/SOI quantum-well MOS device will be more deeply and extensively understood, which provides theoretical supports for design optimization and scattering manipulation to further leverage high mobility advantage of Si/SiGe/SOI quantum-well MOS device.

随着集成电路工艺特征尺寸步入纳米级，传统CMOS技术将遇到迁移率退化、功耗密度过高所带来的严峻挑战。高迁移率器件是应对这些挑战最重要的技术途径。在众多高迁移率器件中，Si/SiGe/SOI量子阱MOS器件是未来提升p-MOS器件空穴迁移率的有效方案之一。本项目针对Si/SiGe/SOI量子阱MOS器件中的原理性问题，对SiGe沟道载流子散射机理进行深入研究，考察声子散射、库仑散射、合金散射等散射机制对器件迁移率的影响，同时系统性研究SiGe层厚度、Ge组分、应力、表面硅层、栅介质等因素对载流子散射机制及迁移率的作用。通过本项目的研究，旨在深入全面地掌握Si/SiGe/SOI量子阱MOS器件载流子散射机理，为优化器件设计、控制散射机制提供理论依据，进一步发挥Si/SiGe/SOI量子阱MOS器件的高迁移率优势。

SiGe沟道MOS器件是未来提升p-MOSFET器件空穴迁移率的有效方法之一。本课题针对Si/SiGe/SOI量子阱MOS器件中的原理性问题，对SiGe沟道的载流子散射机理进行了深入研究。首先成功制备出一系列不同结构和材料参数的高性能Si/SiGe/SOI量子阱p-MOSFET器件。进而通过常温及超低温电学测试，对不同Ge组分、SiGe应力、不同high-k介质的器件的空穴迁移率进行了有效提取。通过创新的SiGe内部电荷分布和散射机制分离等分析方法，有效分析了Si/SiGe/SOI量子阱器件中的声子散射、库伦散射和合金散射等机制的竞争关系。结果显示声子散射在温度高于150K时对SiGe量子阱器件中空穴迁移率起到主导作用，而库伦散射则在150K以下低温下起主要影响。此外，SiGe量子阱器件中的合金散射在低场和高场下对器件的影响程度也差异较大。结果显示合金散射仅在低电场下对空穴迁移率起一定影响。最后，我们还将高迁移率Si/SiGe/SOI量子阱器件用于生化传感应用。制备出的Si/SiGe/SOI量子阱离子敏感场效应晶体管（ISFET）相比SOI ISFET，电压灵敏度显著提高，并展现了很好的线性度。综合上述结果，本研究为探讨SiGe沟道载流子迁移率的散射机理奠定了坚实的工作基础，为优化器件结构与工艺，最大程度发挥SiGe沟道的高迁移率优势提供了理论依据。项目资助发表SCI期刊论文17篇，国际会议论文2篇。培养博士生4名，硕士生3名，其中2名博士、1名硕士已取得学位毕业。项目投入经费25万元，支出24.76万元，剩余经费0.24万元，各项支出基本与预算相符。