Dielectric Interfaces on Doped Diamond Surfaces

非技术描述：金刚石是一种晶体材料，与构成现代电子学基础的硅具有相同的晶体结构。实验室生长方法的最新进展提供了适合制造电子器件的金刚石片。与硅相比，金刚石的独特特性使其成为电力和高频电子产品的终极半导体，在这些领域，金刚石电子产品可以实现更高效的电子汽车，更高效、更智能的电网，以及更高效的通信系统。推进金刚石电子学的最大挑战之一是制造介电界面，使在金刚石晶圆上制造晶体管成为可能。本研究结果为新一代高功率高频器件提供了金刚石介电界面的电子特性。这项研究为学生提供了实验室训练，以推进将推动这一领域的科学和技术。该项目与Sundial合作，Sundial是亚利桑那州立大学的一个项目，支持物理科学的保留和多样性。与日晷一起开展的活动包括与研究有关的讲习班和面向社区成员以及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改善这些学生的保留和教育充实机会，增加传统上代表性不足的学生获得科学职业的机会。技术描述：推进金刚石电子学的最大挑战之一是开发稳定，低缺陷的介电层，将电子和空穴限制在金刚石的导电带和价带中。本课题采用微波等离子体增强化学气相沉积技术在单晶衬底上制备掺杂外延金刚石层。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，表面电子亲和度的变化超过3ev。一个项目的目标是确定p型和n型金刚石表面的电子亲和度、带弯曲、功函数、表面费米能级位置和表面态的存在。将表征良好的掺杂金刚石表面与原位光电发射测量相结合，确定了金刚石上宽禁带介电层的能带偏移。三个特定的层建立了独特的界面性质：1)高功函数和高电子亲和氧化物（如钼氧化物）表现出不同寻常的表面转移掺杂特征；ii)水作为电介质，使掺杂金刚石能够进行光化学过程，以及iii)利用f端金刚石表面的超宽带隙氟化物层。该研究为全面了解金刚石介质层的带向提供了依据，并为器件设计提供了指导。

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.