Controlling AlInGaN/Silicon Interface Kinetics

非技术描述：该项目的重点是提高对硅上氮化物基材料合成的理解，结合两种最广泛使用的半导体-硅和氮化物。尽管它们在发光二极管（LED），功率晶体管和高效太阳能电池等各种器件中具有重要意义，但关于这些重要材料之间界面处发生的晶体生长过程仍有很多未知之处。为了实现这些材料的下一代器件的集成，需要更好地理解界面化学，生长机制，冶金反应，并在这个重要的界面处形成缺陷。该项目利用最近开发的低温晶体生长工艺，能够实现商业上有利的高吞吐率，通过各种分析来研究复杂的界面现象，并将III族氮化物的使用扩展到包括难以捉摸的材料AlGaInN。控制这些现象的机制，可能减少缺陷，使未来的应用程序也有针对性。该项目为研究生提供了物理学，材料科学和纳米电子学交叉领域的尖端技术和资源。由此产生的设备平台有可能导致节能设备，通信，太阳能电池和医疗设备技术的创新。社会和学术推广计划扩大到包括小学到高中学生的示范。这项研究提供了新的机会，传播和出版的详细方法，实现（铝镓铟）-氮化物和硅器件integration.Technical Description：本项目探讨了异质结构的发展组成的四元三氮化物（铝镓铟N）和硅的电子和光电器件集成。虽然硅上的AlN在很大程度上被商业化，但是包括GaN、InN、AlGaN和InGaN的所有其他通常可用的III族氮化物合金基本上不直接在硅衬底上实现。此外，生长AlGaInN的四元化合物的艰巨挑战尚未被掌握，尤其是在硅衬底上。控制在III族氮化物/Si界面处自然发生的生长现象的早期尝试限于绝缘氮化铝中间层是可接受的情况，如在横向晶体管如高电子迁移率晶体管（HEMT）中。对于绝缘屏障不可接受的那些情况，如在未来的垂直传导器件中，例如晶体管、LED、太阳能电池和功率器件，有限的科学理解和现有的商业成功已经被证明。最近展示的低温快速生长方法，如生长速率高达9.8微米/小时的金属调制外延（MME），为“冻结”以前认为太具有挑战性的新相提供了新的可能性。由于MME是在极低的温度（对于氮化铟为300摄氏度，对于氮化镓为约500-600摄氏度）下执行的，所以控制界面扩散、消除共晶驱动的衬底蚀刻以及控制界面平面性的能力都是可行的，所有这些都是通过使用动力学限制扩散来实现的。此外，已经被证明可以克服InGaN的相分离挑战，MME也可以克服四元AlGaInN的相同挑战。这项基础研究工作的目标是更好地理解和控制III-氮化物/硅异质结的界面动力学，提供高质量的四元III-氮化物材料，并确定一个更好的解决方案，用于集成在硅上的垂直传导器件，消除了当今硅/氮化物电子产品中常用的绝缘AlN夹层。该项目的成功执行有可能导致III-氮化物和硅之间的化学和冶金相互作用的详细了解，包括扩散和反应系数的量化。这是下一代硅基垂直功率晶体管所需的基础，该晶体管将智能CMOS器件与III族氮化物和LED的增强功率处理能力集成在一起，用于在低成本（甚至可拆卸/一次性）大面积硅衬底上生长的固态照明。

Nontechnical Description: The focus of this project is to develop an increased understanding of the synthesis of nitride-based materials on silicon, combining the two most widely available semiconductors - Silicon and Nitrides. In spite of their importance in a variety of devices such as light-emitting diodes (LEDs), power transistors, and high-efficiency solar cells, much remains unknown about the crystalline growth processes occurring at the interface between these important materials. In order to achieve the integration of these materials for next generation devices, an improved understanding of the interface chemistry, growth mechanisms, metallurgical reactions, and resulting defect formation at this important interface is needed. This project utilizes a recently developed low temperature crystal growth process, capable of achieving commercially advantageous, high-throughput rates with various analyses to study the complex interfacial phenomena and extend the use of III-Nitrides to include the elusive material AlGaInN. A mechanism to control these phenomena, possibly reducing defects and enabling future applications is also targeted. This project provides graduate students access to cutting-edge technology and resources at the intersection of physics, materials science, and nanoelectronics. The resulting device platform has the potential to lead to innovations in energy saving devices, communications, solar cells, and medical device technologies. Social and academic outreach programs are expanded to include demonstrations for elementary to high school students. This research provides new opportunities for the dissemination and publication of detailed methods for achieving (AlGaIn)-Nitride and Silicon device integration.Technical Description: This project explores the development of heterostructures composed of quaternary III-Nitrides (AlGaInN) and Silicon for electronic and optoelectronic device integration. While AlN on Silicon is largely commercialized, all other commonly available III-Nitride alloys including GaN, InN, AlGaN and InGaN are substantially not implemented directly on Silicon substrates. Furthermore, the daunting challenge of growing quaternaries of AlGaInN has not been mastered, especially not on silicon substrates. Early attempts to control the naturally occurring growth phenomena at III-Nitride/Si interfaces were limited to the case where an insulating aluminum nitride interlayer was acceptable, as in lateral transistors like high-electron mobility transistors (HEMTs). For those cases where insulating barriers are not acceptable, as in future vertical conduction devices, e.g. transistors, LEDs, solar cells, and power devices, limited scientific understanding and no existing commercial success has been demonstrated. The recent demonstration of low temperature, rapid growth methods such as Metal Modulated Epitaxy (MME) with growth rates up to 9.8 microns/hr is providing new possibilities to "freeze in" new phases thought previously too challenging. Since MME is performed at extremely low temperatures (300 degrees C for indium nitride and ~500-600 degrees C for gallium nitride), the ability to control the interface diffusion, elimination of eutectic driven substrate etching, and control of interface planarity, all by using kinetically limited diffusion is viable. Furthermore, having already been proven to overcome phase separation challenges of InGaN, MME is viable for overcoming the same challenges of quaternary AlGaInN as well. The goal of this basic research effort is to better understand and control the interface kinetics of III-Nitride/Silicon heterojunctions, provide high quality quaternary III-Nitride materials and identify a better solution for vertical conduction devices integrated on silicon that eliminates the insulating AlN interlayer commonly used in silicon/nitride electronics today. The successful execution of this project has the potential to lead to a detailed understanding of the chemical and metallurgical interactions between III-Nitrides and Silicon including quantification of diffusion and reaction coefficients. This is the foundation required for next generation vertical power transistors on silicon that integrate smart CMOS devices with the enhanced power handling capabilities of III-Nitrides and LEDs for solid-state lighting grown on low-cost (even removable/disposable) large area silicon substrates.