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Quantum transport quality of a processed undoped Ge/SiGe heterostructure

Physical Review B 2023年第4期108卷 045303-045303页

作者： Yi-Xin Li Zhenzhen Kong Shimin Hou Guilei Wang Shaoyun Huang Beijing Key Laboratory of Quantum Devices Key Laboratory for the Physics and Chemistry of Nanodevices Peking University Beijing 100871 People's Republic of China Integrated Circuit Advanced Process R&D Center Institute of Microelectronics Chinese Academy of Sciences Beijing 100029 People's Republic of China School of Integrated Circuits University of Chinese Academy of Sciences Beijing 100049 People's Republic of China Hefei National Laboratory Hefei 230088 People's Republic of China and Beijing Superstring Academy of Memory Technology Beijing 100176 People's Republic of China

A degraded mobility of 5.2×105cm2V−1s−1 but a long quantum scattering time of 2.3 ps at the hole density of 2.25×1011cm−2 were obtained from a two-dimensional hole gas in a processed undoped Ge/SiGe heterostructure Hall-bar field-effect device. The heterostructure was grown by the reduced pressure chemical vapor deposition method and the device fabrications were compatible with well-established semiconductor technology. The percolation density of 0.69×1011cm−2 indicated a very low disorder potential landscape experienced by holes in the strained Ge quantum well. In addition to integer quantum Hall effects (IQHEs) of consecutive filling factors from ν=8 down to 1, we also observed the quantum states at filling factors between ν=1 and 2, and between ν=2 and 3 at 1.71 K. The observation of quantum Hall effects at the inferior mobility confirmed the mobility/quality dichotomy in the ultraclean undoped Ge/SiGe heterostructure. The study explicitly indicated that the device fabrication process likely compromised the transport mobility, whereas the quantum quality was less influenced, and established the heterostructure as an ideal platform for quantum device implementations.

关键词： Electrical properties Fractional quantum Hall effect Quantum Hall effect Quantum wells Two-dimensional electron system Epitaxy Hall bar Methods in transport Shubnikov-de Haas effect

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Reconfigurable continuous-zoom metalens in visible

arXiv

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arXiv 2019年

作者： Cui, Yuan Zheng, Guoxing Chen, Ming Zhang, Yilun Yang, Yan Tao, Jin He, Taotao Li, Zile Electronic Information School Wuhan University Wuhan430072 China NOEIC State Key Laboratory of Optical Communication Technologies and Networks Wuhan Research Institute of Posts and Telecommunications Wuhan430074 China Photonics Research Centre Guilin University of Electronic Technology Guilin541004 China Integrated Circuit Advanced Process Center Institute of Microelectronics of Chinese Academy of Sciences Beijing100029 China

Design of a conventional zoom lens is always challengeable because it requires not only sophisticated optical design strategy, but also complex and precise mechanical structures for lens adjustment. In this paper, we propose a continuous zoom lens consisting of two chiral geometric metasurfaces with dielectric nanobrick arrays sitting on a transparent substrate. The metalens can continuously vary the focal length by rotating either of the two metasurfaces along its optical axis without changing any other conditions. More importantly, because of the polarization dependence of the geometric metasurface, the positive and negative polarities are interchangeable in one identical metalens only by changing the handedness of the incident circularly polarized light, which can generate varyingfocal lengths ranging from ..,V to +.,V in principle. On account of its advantages of compactness, flexibility and easiness in design, the proposed zoom metalens can provide new perspectives for the development of continuous-zoom optical system and it can find applications in fields which require ultracompact and continuous-zoom imaging and reconfigurable beam wavefront steering. Copyright © 2019, The Authors. All rights reserved.

关键词： Optical design

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Singlet-triplet-state readout in silicon metal-oxide-semiconductor double quantum dots

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Physical Review Applied 2024年第3期21卷 034022-034022页

作者： Rong-Long Ma Sheng-Kai Zhu Zhen-Zhen Kong Tai-Ping Sun Ming Ni Yu-Chen Zhou Yuan Zhou Gang Luo Gang Cao Gui-Lei Wang Hai-Ou Li Guo-Ping Guo CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei Anhui 230026 China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei Anhui 230026 China Integrated Circuit Advanced Process R&D Center Institute of Microelectronics Chinese Academy of Sciences Beijing 100029 China Hefei National Laboratory University of Science and Technology of China Hefei 230088 China Beijing Superstring Academy of Memory Technology Beijing 100176 China Origin Quantum Computing Company Limited Hefei Anhui 230026 China

High-fidelity singlet-triplet state readout is essential for large-scale quantum computing. However, the widely used threshold method of comparing a mean value with the fixed threshold will limit the judgment accuracy, especially for the relaxed triplet state, under the restriction of relaxation time and signal-to-noise ratio. Here, we achieve an enhanced latching readout based on Pauli spin blockade in a Si-MOS double quantum dot device and demonstrate an average singlet-triplet-state readout fidelity of 97.59% by the threshold method. We reveal the inherent deficiency of the threshold method for the relaxed triplet-state classification and introduce machine learning as a noise-resilient and relaxation-independent readout method to reduce the misjudgment. The readout fidelity for classifying the simulated single-shot traces can be improved to 99.67% by the machine-learning method, better than the threshold method of 97.54%, which is consistent with the experimental result. This work indicates that the machine-learning method can be a strong potential candidate for alleviating the restrictions of stably achieving high-fidelity and high-accuracy singlet-triplet-state readout in large-scale quantum computing.

关键词： Optoelectronics Quantum information with solid state qubits Quantum measurements Radio frequency techniques Spin blockade Double quantum dots Elemental semiconductors Machine learning

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CMP-less ILD0 Planarization Technology for Gate-Last process

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ECS Transactions 2012年第1期44卷

作者： Lingkuan Meng Huaxiang Yin Integrated Circuit Advanced Process Center Chinese Academy of Sciences 3 Beitucheng West Road Beijing Beijing 100029 China Chinese Academy of Sciences

As CMOS technology scales to 32nm node and beyond, ILD0 planarization is one of critical technologies in high-K metal gate-last process integration. In this paper, a novel sub-micron gate-last process featuring with CMP-less spin-on glass/silicon oxide (SOG/SiO2) etch-back method was demonstrated for low cost logic platform. The innovative approach of SOG two steps plasma etch-back with O2 treatment can be successfully used for ILD0 planarization of gate-last process. SEM results indicated that there was fairly little 'dish effect' and step height close to zero on the 0.4µm gate-stack array and finally achieved a good planarization on the whole substrate.

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process Impact and Design Optimization on the Soft Yield of 25nm FinFET SRAM Cells

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ECS Transactions 2011年第1期34卷

作者： Meng Li Qingqing Liang Huilong Zhu Huicai Zhong Dapeng Chen Tianchun Ye Integrated Circuit Advanced Process Center Chinese Academy of Sciences No. 3 Bei Tu Cheng West Road Beijing Beijing 100029 China Institute of Microelectronics Chinese Academy of Sciences Institute of Microelectronics Chinese Academy of Sciences No.3 BeiTuCheng West Rd. Beijing Beijing 100029 China Integrated Circuit Advanced Process Center Institute of Microelectronics Chinese Academy of Sciences

A simulation methodology to correlate process variations to the soft yield of 6-T FinFET SRAM cells is demonstrated. By using the TCAD tool which is calibrated to the recently published 25nm FinFET technology, process impacts on the device electrical characteristics are simulated and stored in behavioral models. circuit simulations can then be carried out to calculate the read/write noise margin. Employing the linear function approximation of the noise margin with respect to the six individual process variation parameters in sigma, one can analytically solve the yield when noise margin drops to zero. The calculation results show that instead of Vt variation, parasitic resistance fluctuation dominates fails at high bias voltages. A simple design optimization guideline is also demonstrated to reduce Vmin of the given technology (to 0.5V in this work). This methodology can serve as useful guidelines for both process development and device design.

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Dummy Poly Silicon Gate Removal by Wet Chemical Etching

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ECS Transactions 2011年第1期34卷

作者： Tao Young Huaxiang Yin Qiuxia Xu Chao Zhao Jun Feng Li Dapeng Chen Key Laboratory of Microelectronics Devices & Integrated Technology Chinese Academy of Sciences No.3 Bei-Tu-Cheng West Road Beijing Beijing 100029 China Integrated Circuit Advanced Process Center Institute of Microelectronics Chinese Academy of Sciences No. 3 Bei-Tu-Cheng West Road Beijing Beijing 100029 China Integrated Circuit Advanced Process Center Institute of Microelectronics Chinese Academy of Sciences Institute of Microelectronics Chinese Academy of Sciences

For the gate last integration scheme, dummy poly silicon gate removal is one of the indispensable processes either for a high-k first or a high-k last route. In this paper, experimental results of dummy poly silicon gate removal using TetraMethyl Ammonium Hydroxide (TMAH) chemical etching are presented. The preliminary results show that the poly silicon removal rate was highly sensitive to the wet etch conditions. By optimizing the wet etch conditions, high selectivity of poly silicon with respect to SiO2, Si3N4 and hafnium silicon oxynitride (HfSiON) was obtained. A gate trench of critical dimension (CD) of about 70 nm without poly silicon residue was fabricated using optimized conditions. The excellent etch capability of the optimized wet etch process was also demonstrated by controlling trench profiles.

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Single-spin-qubit geometric gate in a silicon quantum dot

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Physical Review Applied 2024年第1期21卷 014044-014044页

作者： Rong-Long Ma Ao-Ran Li Chu Wang Zhen-Zhen Kong Wei-Zhu Liao Ming Ni Sheng-Kai Zhu Ning Chu Chengxian Zhang Di Liu Gang Cao Gui-Lei Wang Hai-Ou Li Guo-Ping Guo CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei Anhui 230026 China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei Anhui 230026 China Integrated Circuit Advanced Process R&D Center Institute of Microelectronics Chinese Academy of Sciences Beijing 100029 China School of Physical Science and Technology Guangxi University Nanning 530004 China Hefei National Laboratory University of Science and Technology of China Hefei 230088 China Beijing Superstring Academy of Memory Technology Beijing 100176 China Origin Quantum Computing Company Limited Hefei Anhui 230026 China

Preserving qubit coherence and maintaining high-fidelity qubit control under complex noise environment is an enduring challenge for scalable quantum computing. Here we demonstrate an addressable fault-tolerant single spin qubit with an average control fidelity of 99.12% via randomized benchmarking on a silicon quantum dot device with an integrated micromagnet. Its dephasing time T2∗ is 1.025μs, and can be enlarged to 264μs by using the Hahn-echo technique, reflecting strong low-frequency noise in our system. To break through the noise limitation, we introduce geometric quantum computing to obtain high control fidelity by exploiting its noise-resilient feature. However, the control fidelities of the geometric quantum gates are lower than 99%. According to our simulation, the noise-resilient feature of geometric quantum gates is masked by the heating effect. With further optimization to alleviate the heating effect, geometric quantum computing can be a potential approach to reproducibly achieving high-fidelity qubit control in a complex noise environment.

关键词： Geometric & topological phases Quantum gates Quantum information with solid state qubits Elemental semiconductors Quantum dots Single-electron transistors Electron dipole spin resonance Microwave techniques

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Correcting on-chip distortion of control pulses with silicon spin qubits

arXiv

引用

arXiv 2023年

作者： Ni, Ming Ma, Rong-Long Kong, Zhen-Zhen Chu, Ning Liao, Wei-Zhu Zhu, Sheng-Kai Wang, Chu Luo, Gang Liu, Di Cao, Gang Wang, Gui-Lei Li, Hai-Ou Guo, Guo-Ping Cas Key Laboratory of Quantum Information University of Science and Technology of China Anhui Hefei230026 China Cas Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Anhui Hefei230026 China Integrated Circuit Advanced Process R&d Center Institute of Microelectronics Chinese Academy of Sciences Beijing100029 China Hefei National Laboratory University of Science and Technology of China Hefei230088 China Beijing Superstring Academy of Memory Technology Beijing100176 China Origin Quantum Computing Company Limited Anhui Hefei230026 China

Pulse distortion, as one of the coherent error sources, hinders the characterization and control of qubits. In the semiconductor quantum dot system, the distortions on measurement pulses and control pulses disturb the experimental results, while no effective calibration procedure has yet been reported. Here, we demonstrate two different calibration methods to calibrate and correct the distortion using the two-qubit system as a detector. The two calibration methods have different correction accuracy and complexity. One is the coarse predistortion (CPD) method, with which the distortion is partly relieved. The other method is the all predistortion (APD) method, with which we measure the transfer function and significantly improve the exchange oscillation homogeneity. The two methods use the exchange oscillation homogeneity as the metric and are appropriate for any qubit that oscillates with a diabatic pulse. With the APD procedure, an arbitrary control waveform can be accurately delivered to the device, which is essential for characterizing qubits and improving gate fidelity. Copyright © 2023, The Authors. All rights reserved.

关键词： Qubits

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Singlet-triplet-state readout in silicon-metal-oxide-semiconductor double quantum dots

arXiv

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arXiv 2023年

作者： Ma, Rong-Long Zhu, Sheng-Kai Kong, Zhen-Zhen Sun, Tai-Ping Ni, Ming Zhou, Yu-Chen Zhou, Yuan Luo, Gang Cao, Gang Wang, Gui-Lei Li, Hai-Ou Guo, Guo-Ping CAS Key Laboratory of Quantum Information University of Science and Technology of China Anhui Hefei230026 China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Anhui Hefei230026 China Integrated Circuit Advanced Process R&D Center Institute of Microelectronics Chinese Academy of Sciences Beijing100029 China Hefei National Laboratory University of Science and Technology of China Hefei230088 China Beijing Superstring Academy of Memory Technology Beijing100176 China Origin Quantum Computing Company Limited Anhui Hefei230026 China

High-fidelity singlet-triplet state readout is essential for large-scale quantum computing. However, the widely used threshold method of comparing a mean value with the fixed threshold will limit the judgment accuracy, especially for the relaxed triplet state, under the restriction of relaxation time and signal-to-noise ratio. Here, we achieve an enhanced latching readout based on Pauli spin blockade in a Si-MOS double quantum dot device and demonstrate an average singlet-triplet state readout fidelity of 97.59% by the threshold method. We reveal the inherent deficiency of the threshold method for the relaxed triplet state classification and introduce machine learning as a relaxation-independent readout method to reduce the misjudgment. The readout fidelity for classifying the simulated single-shot traces can be improved to 99.67% by machine learning method, better than the threshold method of 97.54% which is consistent with the experimental result. This work indicates that machine learning method can be a strong potential candidate for alleviating the restrictions of stably achieving high-fidelity and high-accuracy singlet-triplet state readout in large-scale quantum computing. Copyright © 2023, The Authors. All rights reserved.

关键词： Semiconductor quantum dots

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A diverse set of two-qubit gates for spin qubits in semiconductor quantum dots

arXiv

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arXiv 2024年

作者： Ni, Ming Ma, Rong-Long Kong, Zhen-Zhen Chu, Ning Zhu, Sheng-Kai Wang, Chu Li, Ao-Ran Liao, Wei-Zhu Cao, Gang Wang, Gui-Lei Guo, Guang-Can Hu, Xuedong Li, Hai-Ou Guo, Guo-Ping CAS Key Laboratory of Quantum Information University of Science and Technology of China Anhui Hefei230026 China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Anhui Hefei230026 China Integrated Circuit Advanced Process R&D Center Institute of Microelectronics Chinese Academy of Sciences Beijing100029 China Department of Physics University at Buffalo SUNY BuffaloNY14260 United States Beijing Superstring Academy of Memory Technology Beijing100176 China Hefei National Laboratory University of Science and Technology of China Hefei230088 China Origin Quantum Computing Company Limited Anhui Hefei230026 China

To realize large-scale quantum information processes, an ideal scheme for two-qubit operations should enable diverse operations with given hardware and physical interaction. However, for spin qubits in semiconductor quantum dots, the common two-qubit operations, including CPhase gates, SWAP gates, and CROT gates, are realized with distinct parameter regions and control waveforms, posing challenges for their simultaneous implementation. Here, taking advantage of the inherent Heisenberg interaction between spin qubits, we propose and verify a fast composite two-qubit gate scheme to extend the available two-qubit gate types as well as reduce the requirements for device properties. Apart from the formerly proposed CPhase (controlled-phase) gates and SWAP gates, theoretical results indicate that the iSWAP-family gate and Fermionic simulation (fSim) gate set are additionally available for spin qubits. Meanwhile, our gate scheme limits the parameter requirements of all essential two-qubit gates to a common J~∆EZ region, facilitate the simultaneous realization of them. Furthermore, we present the preliminary experimental demonstration of the composite gate scheme, observing excellent match between the measured and simulated results. With this versatile composite gate scheme, broad-spectrum two-qubit operations allow us to efficiently utilize the hardware and the underlying physics resources, helping accelerate and broaden the scope of the upcoming noise intermediate-scale quantum (NISQ) computing. Copyright © 2024, The Authors. All rights reserved.

关键词： Semiconductor quantum dots

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