Nanoscale Germanium Electronics

该提案是一项可行性研究，以确定在锗中制造纳米级电子器件的实用性，尺寸范围从几十纳米到原子尺度。数十亿英镑的半导体工业是建立在硅晶圆上制造的集成电路（ic）的基础上的，并且在过去的40年里，每18个月元件就会变小两倍（摩尔定律）。然而，近年来，由于量子效应，电路元件的小尺寸引入了许多麻烦的器件性能问题，例如隧道效应，而将锗纳入器件元件被视为一种潜在的解决方案。上述量子效应的一个积极方面，在接近纳米尺度的设备中可以看到，明确利用量子力学的新设备范例正在为未来几代集成电路和量子信息处理（QIP）应用进行探索。例如，有人提出用锗中的杂质或应变Si-Ge异质结构中的掺杂剂制造量子计算机。因此，了解纳米级锗器件的电输运以及锗中单一掺杂剂和相互作用掺杂剂的量子特性变得至关重要。为了为锗纳米级掺杂器件的制造提供一条清晰的途径，将开发以下技术：(i)以原子精度将掺杂原子放置在锗晶体的受控位置，以便了解其基本特性；（ii）在锗中制造并电学表征埋藏的1原子厚掺杂层（δ掺杂层）。这项技术将利用扫描隧道显微镜（STM），它可以对一个原子一个原子地进行成像和操作，绘制出由氢原子构成的单原子厚的抗蚀剂层的图案，由前驱体气体提供掺杂剂。然后将使用相同的STM来表征制造结构。

This proposal is a feasibility study to determine the practicality of fabricating nanoscale electronic devices in germanium, of dimensions ranging from tens of nanometres to the atomic scale. The multi-billion pound semiconductor industry is based on integrated circuits (ICs) fabricated on silicon wafers and has been for the last forty years, with components being made smaller by a factor of two every eighteen months (Moore's Law). However, in recent years, the small size of circuit components has introduced a number of troublesome device performance issues due to quantum effects, such as tunnelling, and the incorporation of germanium into device components is seen as a potential solution. One positive aspect of the above mentioned quantum effects, seen in devices approaching nanoscale dimensions, is that new device paradigms which explicitly exploit quantum mechanics are being explored for future generations of ICs and for quantum information processing (QIP) applications. For example there are interesting proposals to make quantum computers from impurities in germanium or from dopants in strained Si-Ge heterostructures. Thus it has become crucial to understand the electrical transport through nanoscale germanium devices and the quantum properties of single and interacting dopants in germanium. In order to provide a clear pathway towards the fabrication of germanium nanoscale dopant devices, techniques will be developed to (i) place dopant atoms at controlled positions in a germanium crystal, with atomic precision, in order to learn about their fundamental properties and (ii) fabricate and electrically characterise buried 1-atom thick dopant layers (delta-doped layers) in germanium. The techniques will utilise a scanning tunnelling microscope (STM), which can image and manipulate matter atom-by-atom, to pattern a single atom thick resist layer made from hydrogen atoms, with a precursor gas supplying the dopants. The same STM will then be used to characterise the fabricated structures.