Chemical Routes to the Growth of Crystalline Oxides Directly on Germanium for Applications in Future Generation Microelectronic Devices

目前，大多数为微电子器件供电的晶体管都是基于硅的。虽然近年来硅基微电子器件的速度有了显著的提高，但硅基芯片的运行速度受到材料本身的限制，为了制造更快的器件，需要一种新的半导体材料。锗就是这样一种很有前途的材料，可以用来制造更快的计算机芯片。制造晶体管的一个关键挑战是需要一个好的电子半导体和一个与半导体兼容的好的绝缘体。为了使基于锗的芯片工作，需要一个好的电绝缘体。该奖项旨在开发和理解一种与锗兼容的新型电绝缘体，并可用于制造基于锗的微电子产品。这项研究的更广泛影响将是晶体管的持续缩小，这将为微电子设备提供更快的计算机处理器速度、更低的功耗和更高的数据存储容量。本研究考察了钙钛矿在锗晶体管中作为介电氧化物的用途。选择钙钛矿是因为它们能够化学地与锗结合，并消除影响设备性能的电气缺陷。这项工作将探索如何在锗上生长晶体钙钛矿氧化物膜，以满足现代微电子器件的许多性能要求。该研究探索了一种全化学生长过程，该过程应该是可扩展的，本质上成本更低，并且基于当前的制造工具基础设施，以促进易于被工业采用。本研究探索并描述了利用原子层沉积工艺在锗上生长SrHfO3和SrZrO3晶体的材料化学和表面化学。总体目标是理解和描述在化学沉积过程中导致Ge（001）上形成具有必要能带偏移和界面陷阱密度的晶体氧化物的过程。这项工作的智力价值源于基础研究的特定重点领域，即：1)阐明Ge（001）氧化物界面的反应和结构变化，这些反应和结构变化是形成晶体氧化物的种子；2)了解钙钛矿层中导致结晶膜的结构演变以及结构如何依赖于工艺条件；3)建立场效应晶体管中栅极氧化物的结构-性能-功能关系。

Presently, the majority of transistors that power microelectronic devices are based on silicon. While there have been significant increases in speed of silicon-based microelectronic devices in recent years, the speed at which silicon-based chips can operate is limited by the material itself, and in order to make faster devices a new semiconductor material is required. Germanium is one such promising material that can enable manufacturing of faster computer chips. One critical challenge in building transistors is the need for a good electrical semiconductor and a good insulator that is compatible with that semiconductor. To make germanium-based chips work, a good electrical insulator is needed. This award is to develop and understand a new type of electrical insulator that is compatible with germanium and which can allow for manufacturing of germanium-based microelectronics. The broader impact of the research will be in continued scaling of transistors to smaller sizes that will provide faster computer processor speeds, lower power consumption, and higher data storage capacities for microelectronic devices. This research examines perovskites for use as dielectric oxides in germanium transistors. Perovskites are selected for their ability to bond chemically to germanium and eliminate the electrical defects that affect device performance. This work will explore how to grow crystalline perovskite oxide films on germanium that meet the many performance requirements of modern microelectronic devices. The research explores an all-chemical growth process that should be scalable, is inherently less costly, and is based on current manufacturing tool infrastructure to promote easy adoption by industry. The research explores and describes the materials chemistry and the surface chemistry associated with growing crystalline SrHfO3 and SrZrO3 on germanium using atomic layer deposition processes. The overarching objectives are to understand and describe processes that lead to the formation of crystalline oxides on Ge (001) with requisite band offsets and interface trap densities in a chemical deposition process. The intellectual merits of the work stem from the specific focus areas of the fundamental studies which are: 1) elucidating the reactions and structural changes at the Ge (001) oxide interface that seed crystalline oxide formation; 2) understanding the evolution of structure in the perovskite layer leading to a crystalline film and how the structure depends on process conditions; and 3) establishing the structure-property-function relationships in the context of a gate oxide in a field effect transistor application.