硅衬底上III-V族异质结材料生长机制和HEMT器件制备研究

This project is focused on the hetero-structure material growth of III-V semiconductor layer based on silicon substrate, the fabrication of the deep submicron silicon-based high electron mobility transistor (HEMT) devices and the model of devices. The dislocation and defects formation of silicon/III-V semiconductor materials due to larger lattice constant mismatch and the growth mechanism will be studied as the key research. The growth technique of the buffer layer will be investigated, which have much effects on the HEMT material crystal quality and interface characteristics between different epi-layers. By optimizing the growth conditions of silicon/III-V semiconductor epitaxial layer, we will summarize the law of high and low temperature eip-layer growth, the discontinuous growth and super-lattice structure, which influence the defects and blocking of epitaxial material. It is finally to obtain the solution of epitaxial growth of III-V semiconductors based on silicon substrate. To research the tunneling effect of nano-scale HEMT devices based on silicon substrate, the ballistic transport of non-equilibrium carriers and the fluctuation phenomenon caused by micro statistics. Using Hydrodynamic and Monte Carlo approaches to simulate the carrier transport rules of the nano-scale, femtosecond conditions, to establish an accurate physical model describing the UHF, nanoscale semiconductor devices, and provide theory in order to realize the electronic device developed by Gichz to the THz.

本项目主要开展硅衬底上III-V族半导体材料异质生长机制、深亚微米硅基高电子迁移率晶体管（HEMT）器件制备和器件模型等方面研究。研究硅衬底/III-V族半导体材料之间由于晶格常数大失配等引起的位错、缺陷和生长质量不高等关键问题。研究硅衬底缓冲层生长技术对HEMT材料的晶体质量和界面特性的影响，通过优化Si/III-V族半导体外延层的生长条件，总结高低温生长、间断生长和超晶格结构对外延材料缺陷的产生和阻断的影响规律，最终获得一整套在硅基上外延生长III-V族半导体的技术解决方案。研究纳米尺度硅基HEMT器件的隧穿效应、非平衡载流子的弹道输运以及微观统计引起的涨落等现象，采用Hydrodynamic与Monte Carlo模拟方法研究纳米尺度、飞秒量级下载流子输运规律，建立准确描述超高频、纳米尺度半导体器件的物理模型，为实现电子器件由吉赫兹向太赫兹发展提供理论基础。

本项目对硅基III-V族HEMT外延材料、制备工艺和模型开展了相关的研究，分别研究了HEMT器件外延材料结构的设计、结构仿真、材料外延生长、器件关键工艺技术、器件测试分析，以及器件模型等方面。通过优化设计硅基高In组分复合沟道的HEMT材料，外延生长出低缺陷密度、高迁移率、稳定可靠的硅基高In组分复合沟道的HEMT材料，在常温下HEMT材料的2DEG迁移率大于8000cm2/V.s，2DEG浓度大于1.8E12cm-2，方块电阻200ohm/squ.。开展了硅基高In组分复合沟道的HEMT器件制备关键工艺的研究。开展了基于Ti/Pt/Au欧姆接触系统在InGaAs HEMT制备中的应用研究，在300℃/30s的合金条件下，得到了低欧姆接触电阻（0.025Ω•mm）。同时在温度360℃/60s退火条件下，进行了可靠性实验，实验结果表明器件的欧姆接触性能和直流性能无显著变化，表明其具有较好的温度稳定性。开发出电子束光刻三层胶的T型栅制备工艺流程，攻克了栅长小于100nm的T型栅工艺的关键技术。开发了深亚微米的硅基HEMT器件完整工艺流程，开展了器件参数提取和建模的相关研究。制备成功80nm栅长的HEMT器件，测试与分析了器件的性能。测试结果表明器件实现了优良的高频性能，其漏极饱和电流为0.86A/mm，非本征跨导为1.1S/mm，特征频率(fT)为246GHz，最大振荡频率(fmax)为301GHz。此项成果可以为未来成本低、大规模产业化的硅基半导体和具有优异电子性能的化合物材料异质集成开辟出另一条崭新的发展路线。