Spin Qubits Confined to a Silicon Nano-Ridge
Spin Qubits Confined to a Silicon Nano-Ridge
复制标题
DOI：
10.3390/app9183823
复制
发表时间：
2019-09-01
影响因子：
2.7
通讯作者：
Schreiber, L. R.
中科院分区：
文献类型：
--
作者：
Klos, J.;Sun, B.;Schreiber, L. R.
硅中的静电定义量子点（QD）是量子计算的一个有吸引力的平台。局域化的单电子自旋定义了量子比特，并提供了出色的操作和读出能力。我们提出了一种可扩展的硅基量子比特器件，可以通过行业兼容的工艺制造。该器件由沿着蚀刻的硅纳米脊定位的密集的量子点阵列组成。由于其横向限制，金属顶栅的简单密集阵列形成具有可控隧道耦合的量子点阵列。为了避免由于纳米脊侧壁处的粗糙度和带电缺陷而引起的电势波动，纳米脊的横截面是梯形的并且由原子级平坦的{111}刻面界定。除了在低缺陷氧化{111}面顶部的侧栅之外，我们还通过使用绝缘体上硅来实现全局背栅。最相关的工艺模块的实验证明，包括各向异性湿法刻蚀和局部氧化的硅纳米脊，侧栅形成与化学机械抛光，和顶栅制造采用的间隔工艺。根据静电模拟，我们的器件概念允许形成电容耦合QD双阵列或相邻的电荷检测器用于自旋读出。定义一个逻辑量子位或实现一个用于中程量子位耦合的单电子传输器将是未来的应用。
Electrostatically-defined quantum dots (QDs) in silicon are an attractive platform for quantum computation. Localized single electron spins define qubits and provide excellent manipulation and read-out fidelities. We propose a scalable silicon-based qubit device that can be fabricated by industry-compatible processes. The device consists of a dense array of QDs localized along an etched silicon nano-ridge. Due to its lateral confinement, a simple dense array of metallic top-gates forms an array of QDs with controllable tunnel-couplings. To avoid potential fluctuations because of roughness and charged defects at the nano-ridge sidewall, the cross-section of the nano-ridge is trapezoidal and bounded by atomically-flat {111} facets. In addition to side-gates on top of the low-defect oxidized {111} facets, we implement a global back-gate facilitated by the use of silicon-on-insulator. The most relevant process modules are demonstrated experimentally including anisotropic wet-etching and local oxidation of the silicon nano-ridge, side-gate formation with chemical-mechanical polishing, and top-gate fabrication employing the spacer process. According to electrostatic simulations, our device concept allows forming capacitively-coupled QD double-arrays or adjacent charge detectors for spin-readout. Defining a logical qubit or realizing a single electron conveyor for mid-range qubit-coupling will be future applications.