同步辐射研究铪基高k介质/InGaAs界面特性及元素扩散调控

This project is to solve the key problems in the advanced integrated circuit technology for the application at the node below 10 nm. It will investigate the interfacial properties and its elements diffusions at the interface of hafnium-based high dielectric constant (high-k) insulators/InGaAs semiconductor. The study will firstly focus on the surface and interface chemical reaction mechanism during the interface formation using the synchrotron radiation photoemission microscopy with high resolution and high sensitivity in Shanghai Synchrotron Radiation Facility. With the advanced characterization methods, it can precisely track the diffusions of indium, gallium and arsenic elements from the InGaAs substrate. The effect of atomic layer deposition process and rapid thermal annealing parameters on the element diffusion and their distribution will be investigated emphatically. As a result, the microscopic structures and the component evolution rules at the surface and interface will be clarified at the nanometer scale. Moreover, the influence of the diffusion elements on the dielectric properties of hafnium-based high-k insulators will be studied using synchrotron radiation X-ray absorption spectroscopy and first-principles calculations. It is expected to reveal the intrinsic relationship between the electrical characteristics of the devices and microstructural defects. On this basis, the surface passivation methods using NH3 plasma pretreatments, atomic layer deposition a thin AlN layer, and microwave thermal annealing technology will be proposed to effectively inhibit the interface element diffusions, respectively. It helps to improve the reliability of hafnium-based high-k insulators /InGaAs metal oxide semiconductor (MOS) devices by reducing the interface state density and frequency dispersion effect. The research results can provide some theoretical bases and feasible solutions for developing high performance III-V MOSFETs.

本项目面向10 nm技术节点以下的先进集成电路工艺，开展铪基高介电常数(k)介质/InGaAs半导体界面特性及元素扩散等关键技术研究。拟采用上海光源高分辨、高灵敏度的同步辐射光发射电子显微镜，重点分析铪基高k介质/InGaAs界面形成过程中的表面、界面化学反应机制，精确追踪原子层沉积工艺、快速热退火条件下InGaAs衬底元素In、Ga和As等在高k介质中的扩散过程及其具体分布，从纳米尺度阐明表面、界面微观结构及其组分演变规律。利用同步辐射X射线吸收谱和第一性原理计算分析扩散元素对铪基高k薄膜的介质特性影响，揭示器件电学特性与其微结构缺陷之间的内在关系。在此基础上，提出采用含N表面钝化方法及微波热退火技术来抑制界面元素扩散，有效调控界面特性，掌握提升铪基高k介质/InGaAs金属氧化物半导体(MOS)器件可靠性的关键技术，为研制出高性能的III-V族MOSFETs提供理论依据和解决方案。

本项目主要面向10 nm技术节点以下的先进集成电路工艺，开展高k介质/III-V族半导体界面调控关键共性问题研究。为此本项目将借助高性能的同步辐射和XPS等微纳测试技术，并结合理论计算和电学表征方法，厘清高k介质与InSb、InAs、InP和InGaAs界面的化学反应和元素扩散机制，探讨高k介质/InGaAs界面缺陷的形成机理、演变过程以及湮灭机制并精细控制，揭示器件电学特性与其微结构缺陷之间的内在关系，进而提出控制界面元素扩散的有效钝化方法，为进一步制备出高性能的III-V族晶体管提供实验基础和理论指导。1）利用光电子能谱，同步辐射光电子能谱等技术分别对HCl预处理和天然氧化的InSb、InAs、InGaAs等样品在沉积HfO2、Al2O3等高k介质薄膜前后，以及快速热退火后的界面化学，元素扩散，元素脱吸附现象和表面形貌进行了系统的表征。通过XPS和SRPES表征发现两组样品在沉积完高k介质薄膜后都发生了衬底再氧化及元素的扩散现象栅介质，并优化出相应的制备工艺参数。2）探索了InP、Ge等高迁移率半导体材料与新型的高k 介质之间的能带对准情况研究，为厘清基于新一代IC高迁移率半导体沟道层与高k介质之间的晶体管的电学特性影响因素和分析其内在物理机制，提供理论参考。3）实现了在原子层尺度上高质量HfAlO、HfO2、AlN、AlON、SiO2、Ga2O3等介质薄膜的可控制备，掌握相应的组分精确调控的方法，并获取了相应的工艺参数、生长规律和薄膜质量控制因素。为后续在III-V族衬底上生长相应的高k介质，以及制备半导体相关器件的器件奠定了坚实的基础。