On-Chip milliKelvin Electronic Refrigerator for Astronomical and Quantum Device Applications

我们打算开发一种新的用户友好型技术，使小型设备能够冷却到极低的温度（<100 ℃）。这种能力将使多样化和未来的应用蓬勃发展。其中包括黑洞探测、癌症探测和量子计算。我们建议通过使用电子冷却过程来做到这一点，在该过程中，相对高能（热）的载流子（电子或空穴）量子机械地从介质中隧穿出来，从而导致介质中的平均电子温度降低。应用这种工艺来实现极低温度是非常新的，我们希望通过将新一代半导体SiGe引入电子冷却器的设计中来大大提高其效率，并且沿着发展良好的硅处理技术，从而最终可以经济地生产这种冷却器并达到工业标准。冷却器将围绕一个小硅芯片的外围制造，并与安装在芯片中心的有源器件（有效载荷）进行热连接。这需要非常好的热设计，使得电子冷却器有效地冷却有效载荷。然而，在某些情况下，只需要冷却电子/而不是晶格原子;这里SiGe在控制电子和晶格之间的热耦合方面提供了很大的灵活性。这种电子冷却器可以从0.3K的起始温度开始工作，这可以由无低温流体的闭合循环氦低温恒温器产生，因此可以设想能够进入~ 10 mK工作环境的旋转开关技术。这将是一个巨大的技术进步，因为现有的技术需要大量和复杂的低温流体为基础的设备。在该项目的第一阶段，我们将研究几种方法来实现有效的电子冷却，利用在SiGe及其相关的金属硅化物中可以在非常低的温度下获得的广泛的基本电子条件，从而增强载流子传输和热电效应。然后，新的冷却器将在两个非常热门的领域进行测试，即辐射探测器和量子信息设备。它们可以极大地提高我们探测能力，例如，从最早的黑洞发出的光子，卫星探测器的工作温度低于100 mK。而且，非常重要的是，这种检测器可以彻底改变在生物医学研究中广泛使用的荧光检测，使我们对遗传疾病（例如癌症）和单细胞工作的理解取得进展。此外，量子计算时代所开辟的计算前景需要在10- 20 mK下运行的量子比特设备，这确实令人敬畏。沃里克正在协调该项目，并组建了一个由来自英国四所大学--沃里克、卡迪夫、莱斯特和伦敦（皇家霍洛威）--的具有适当专业知识的科学家和工程师组成的紧密联盟，以及四家领先的公司，他们关注这项技术的发展，并展示其在两个关键领域的适用性和优势。我们还与欧洲领先的mK制冷机中心（赫尔辛基理工大学）密切合作。英国处于非常有利的地位，可以从这种真正新的和令人兴奋的技术中受益，这个项目将为其实现播下种子。

We intend to develop a new user-friendly technology that would enable small devices to be cooled to exceedingly low temperatures (<100mk). Such a capability will allow diverse and futuristic applications to flourish. These include the detection of black holes, cancer detection and quantum computing. We propose to do this by using an electronic cooling process where relatively energetic (hot) carriers (electrons or holes) quantum mechanically tunnel out of a medium, thereby causing the average electronic temperature in the medium to decrease. The application of this process to realise extremely low temperatures is very new, and we want to greatly improve its efficiency by introducing a new generation semiconductor SiGe into the design of the electronic cooler and, along with it, the well developed silicon processing techniques - so that, ultimately, such coolers can be produced economically and to industrial standards. Coolers will be fabricated around the periphery of a small silicon chip with thermal links to the active device ( payload ) mounted in the centre of the chip. This requires very good thermal design such that the electronic cooler efficiently cools the payload. However, in some cases, it is only necessary to cool the electrons / not the lattice atoms; here SiGe gives a lot of flexibility in controlling the thermal coupling between the electrons and the lattice. Such electronic coolers can operate from a starting temperature of 0.3K, which can be produced by a cryogenic fluid-free closed-cycle helium cryostat, so that a turn-switch technology can be envisaged enabling access to ~10mK working environments. This will be a huge technology step forward, as existing techniques require massive and complex cryogenic fluid-based equipment.During the first phase of the project we will examine several approaches to the realisation of effective electronic cooling, exploiting the wide range of fundamental electronic conditions that can be obtained at very low temperatures in SiGe with its associated metal silicides / thereby enhancing carrier transport and thermoelectric effects. The new coolers will then be tested in two areas of great topical interest, namely radiation detectors and quantum information devices. They could dramatically enhance our ability to detect, for example, the photons that emanate from the earliest black holes, with satellite-based detectors operating at <100mK. And, very significantly, such detectors could revolutionize the fluorescence light detection that is used extensively in biomedical research, enabling advances in our understanding of genetically-based diseases (e.g. cancer) and the workings of a single cell. Furthermore, the computational vista that is opened-up by the quantum computing era requiring qubit devices operating at 10-20mK, is truly awe inspiring. Warwick is co-ordinating the project and has assembled a tightly knit consortium of scientists and engineers with appropriate expertise from four UK universities -Warwick, Cardiff, Leicester and London(Royal Holloway) - and four leading-edge companies, concerned with the development of this technology and the demonstration of its applicability and advantages in two key areas. We are also working closely with Europe's leading centre on mK coolers (Helsinki University of Technology). The UK is exceedingly well positioned to derive benefit from this genuinely new and exciting technology, and this project will sow the seeds for its realisation.