Dielectric Interfaces on Doped Diamond Surfaces

非技术性说明：金刚石是一种晶体材料，与硅具有相同的晶体结构，硅是现代电子学的基础。 实验室生长方法的最新进展已经提供了适合于制造电子器件的金刚石板。与硅相比，金刚石的独特性质使其成为功率和高频电子产品的最终半导体，金刚石电子产品可以实现更高效的电子车辆，更高效，更智能的电子电网以及更高效的通信系统。推进金刚石电子技术的最大挑战之一是产生介电界面，从而能够在金刚石晶片上制造晶体管。这项研究的结果为新一代高功率和高频器件提供了对金刚石介电界面电子特性的深入了解。这项研究为学生提供了实验室培训，以推进推动这一领域的科学和技术。该项目与亚利桑那州立大学的日晷项目合作，该项目支持物理科学的保留和多样性。与Sundial一起开发的活动包括与研究相关的研讨会和面向社区成员和当地高中和社区大学学生和教师的外联级科学会议。这些活动的目标是通过提高学生的保留率和教育机会，增加传统上代表性不足的学生进入科学事业的机会。技术说明：推进金刚石电子学的最大挑战之一是开发稳定的低缺陷电介质层，将电子和空穴限制在金刚石的导带和价带中。本计画利用微波电浆增强化学气相沈积法在单晶基板上制备掺杂磊晶钻石层。金刚石的一个独特之处在于，通过控制H、O或F的表面终止，表面电子亲和力的变化超过3 eV。一个项目的目标是确定电子亲和势，能带弯曲，功函数，表面费米能级的位置和存在的p型和n型金刚石表面上的表面状态。利用掺杂金刚石表面的光电子能谱测量方法，研究了金刚石表面宽带隙电介质层的能带偏移。三个特定的层建立了独特的界面特性：i）高功函数和高电子亲和力的氧化物（例如氧化钼），其显示出不寻常的表面转移掺杂特性; ii）水作为电介质，其能够在掺杂的金刚石上进行光化学过程;以及iii）利用F-终止的金刚石表面的超宽带隙氟化物层。该研究提供了对金刚石上介电层能带排列的全面理解，并为器件设计提供指导。

Non-technical description: Diamond is a crystalline material that shares the same crystal structure with silicon, which has formed the basis of modern electronics. Recent advances in laboratory growth methods have provided diamond plates suitable for fabricating electronic devices. Compared to silicon, the unique properties of diamond make it the ultimate semiconductor for power and high frequency electronics, where diamond electronics could enable more efficient electronic vehicles, a more efficient and smarter electronic grid, and more efficient communication systems. One of the greatest challenges to advancing diamond electronics is producing dielectric interfaces that can enable fabrication of transistors on diamond wafers. The outcomes of this research provides insight into the electronic properties of dielectric interfaces on diamond for a new generation of high power and high frequency devices. The research provides laboratory training for students to advance the science and technology that will drive this field. This project collaborates with Sundial, a program at Arizona State University which supports retention and diversity in the physical sciences. The activities developed with Sundial include research related workshops and an outreach-level scientific conference, geared to community members and local high school and community college students and teachers. The goals of these activities are to increase access to science careers to students who are traditionally under-represented, by improving retention and educational enrichment opportunities for these students.Technical description: One of the greatest challenges to advancing diamond electronics is the development of stable, low defect dielectric layers that confine electrons and holes in the conduction and valence band of diamond. This project uses doped epitaxial diamond layers prepared by microwave plasma enhanced chemical vapor deposition on single crystal substrates. A unique aspect of diamond is that the surface electron affinity varies by more than 3 eV by controlling the surface termination with H, O or F. A project goal is to determine the electron affinity, band bending, work function, surface Fermi level position and presence of surface states on the p- and n-type diamond surfaces. The well-characterized doped diamond surfaces are used with in situ photoemission measurements to determine the band offsets of wide bandgap dielectric layers on diamond. Three specific layers establish the unique interface properties: i) high work function and high electron affinity oxides (e.g. molybdenum oxide) that have shown unusual surface transfer doping characteristics; ii) water as a dielectric that enables photochemical processes on doped diamond, and iii) ultra-wide band gap fluoride layers that take advantage of the F-terminated diamond surface. The research provides a comprehensive understanding of the band alignment of dielectric layers on diamond and provides guidance for device design.