High yield, low variability – Employing silicon CMOS technology for the realization of spin qubits

高产量、低变异性 – 采用硅 CMOS 技术实现自旋量子位

• 批准号: 421769186
• 负责人: Professor Dr. Joachim Knoch
• 金额: --
• 依托单位: Institut für Halbleitertechnik (IHT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/421769186?language=en
• 关键词: yield; low; variability; Employing; silicon

In recent years, all building blocks for quantum computation using spin qubits were demonstrated in electrostatically defined spin qubits based on e.g. GaAs or Si. Remaining manipulation infidelities are tolerable by using a surface code which requires a large number of physical qubits. As a result, the feasibility of a spin qubit quantum computer is directly related to the scalability of the system. However, even state-of-the-art qubit realizations rely on a rather immature fabrication technology with very low yield and large device-to-device variability. Furthermore, complex multi-layer gate patterns will be required to improve the confinement potentials and to realize new functionalities e.g. a quantum bus. In the current project a qubit technology will be developed that is based on fabrication techniques derived from industrial silicon CMOS technology ensuring scalability and a high yield of our approach. Due to the low-temperature operation and in order to guarantee tunability of the qubits a very large number of nanoscale gate electrodes will be realized on top of a semiconductor heterostructure in which the single electron spin representing qubits will be defined electrostatically. For the realization of these gate structures we will use the so-called (multiple) spacer process which not only avoids the need for highly sophisticated nanolithography (such as electron-beam lithography). More importantly, it significantly reduces the device-to-device variability. This strongly increases the yield and in addition might even allow a reduction of the total number of gates necessary to electrostatically tune the individual qubits. The fabrication will be carried out with the lowest possible ther-mal budget such that the impact on the heterostructure is minimized (e.g. no reduction of valley splitting in Si/SiGe quantum wells) and that the developed technology can be used for different substrates such as GaAs/AlGaAs.Throughout the project MBE-grown Si/SiGe multi-quantum dot samples will be fabricated. The gate-tunability of the quantum dots, the electrostatic noise and the valley splitting are determined by transport measurements at ~20 mK. Qubit functionality such as charge-readout by an adjacent read-out quantum dot and spin-to-charge conversion will be demonstrated. Within the project we aim at extending the number of quantum dots to 40 without losing tunability and functionality of each quantum dot. The multi-quantum dot samples allow mapping the valley splitting variability over a large area. Combining the development of appropriate fabrication technologies to facilitate groundbreaking work on multi quantum dot/qubit devices our approach has the potential to provide highly relevant contributions to the science and technology of the field. Furthermore, since the technology devel-opment will be as close as possible to current industrial processes it may help accelerating the realization of future quantum information processors.

近年来，基于例如GAAS或SI。通过使用需要大量物理Qub的表面代码，剩余的操纵不忠是可以忍受的。结果，自旋量子量子计算机的可行性与系统的可扩展性直接相关。但是，即使是最先进的量子实现，也依赖于一种不成熟的制造技术，其产量非常低，设备到设备的可变性很大。此外，将需要复杂的多层门模式来提高限制电位并实现新的功能，例如量子总线。 在当前项目中，将开发基于工业硅CMOS技术的制造技术，以确保可伸缩性和高收率。由于低温操作并为了确保Qubits的可调性，将在半导体异质结构的顶部实现大量纳米级门电极，其中将在静电上定义单个电子自旋代表。为了实现这些栅极结构，我们将使用所谓的（多个）间隔过程，该过程不仅避免了对高度复杂的纳米光刻（例如电子束光刻）的需求。更重要的是，它大大降低了设备到设备的变异性。这大大提高了产量，此外，甚至可能允许减少静电调节单个Qubits所需的大门数量。该制造将以最低的预算进行，以使对异质结构的影响最小化（例如，在Si/Sige量子井中没有减少山谷拆分），并且可以将开发的技术用于GAAS/ALGAAS.THOUGHOUGHOUD.THROUGHOUD。量子点，静电噪声和山谷分裂的栅极可承受性由〜20 mk的传输测量确定。将展示量子功能，例如通过相邻读取量子点进行电荷阅读和旋转电荷转换。在项目中，我们旨在将量子点的数量扩大到40，而不会丢失每个量子点的可调性和功能。多量子点样品允许在大面积上绘制山谷分裂的变化。结合适当的制造技术的开发，以促进在多量子点/Qubit设备上进行开创性的工作，我们的方法有可能为该领域的科学和技术提供高度相关的贡献。此外，由于技术开发将尽可能接近当前的工业流程，因此可能有助于加速未来的量子信息处理器的实现。