[paper] Characterization and Modeling of SOI LBJTs at 4K

Yuanke Zhang, Yuefeng Chen, Yifang Zhang, Jun Xu, Chao Luo, and Guoping Guo

Characterization and Modeling of Silicon-on-Insulator 

Lateral Bipolar Junction Transistors at Liquid Helium Temperature

IEEE TED Vol. XX, No. XX, preprint arXiv:2309.09257 (2023).

University of Science and Technology of China (USTC), Hefei 230026, Anhui, China

CAS Key Lab ofQuantum Information, Hefei 230026, Anhui, China.

Abstract: Conventional silicon bipolars are not suitable for low-temperature operation due to the deterioration of current gain (β). In this paper, we characterize lateral bipolar junction transistors (LBJTs) fabricated on silicon-on insulator (SOI) wafers down to liquid helium temperature (4 K). The positive SOI substrate bias could greatly increase the collector current and have a negligible effect on the base current, which significantly alleviates β degradation at low temperatures. We present a physical-based compact LBJT model for 4 K simulation, in which the collector current (IC) consists of the tunneling current and the additional current component near the buried oxide (BOX)/silicon interface caused by the substrate modulation effect. This model is able to fit the Gummel characteristics of LBJTs very well and has promising applications in amplifier circuits simulation for silicon-based qubits signals.

Fig: IC (solid lines) and IB (dash lines) versus VBE of LBJT at different temperatures 

under (a) VBOX = 0 V; (b) VBOX = 12 V, VCE = 1 V.

Acknowledgement: The device fabrication was done by Prof. Zhen Zhang’s group in the Angstrom Microstructure Laboratory (MSL) at Uppsala University. Dr. Qitao Hu, Dr. Si Chen, Prof. Zhen Zhang are acknowledged for the device design and fabrication, and the technical staff of MSL are acknowledged for their process support.

Palace: 3D Finite Element Solver for Computational Electromagnetics

Palace, for PArallel LArge-scale Computational Electromagnetics, is an open-source, parallel finite element code for full-wave 3D electromagnetic simulations in the frequency or time domain, using the MFEM finite element discretization library.

Key features:

• Eigenmode calculations with optional material or radiative loss including lumped impedance boundaries. Automatic postprocessing of energy-participation ratios (EPRs) for circuit quantization and interface or bulk participation ratios for predicting dielectric loss.
• Frequency domain driven simulations with surface current excitation and lumped or numeric wave port boundaries. Wideband frequency response calculation using uniform frequency space sampling or an adaptive fast frequency sweep algorithm.
• Explicit or fully-implicit time domain solver for transient electromagnetic analysis.
• Lumped capacitance and inductance matrix extraction via electrostatic and magnetostatic problem formulations.
• Support for a wide range of mesh file formats for structured and unstructured meshes, with built-in uniform or region-based parallel mesh refinement.
• Arbitrary high-order finite element spaces and curvilinear mesh support thanks to the MFEM library.
• Scalable algorithms for the solution of linear systems of equations, including geometric multigrid (GMG), parallel sparse direct solvers, and algebraic multigrid (AMG) preconditioners, for fast performance on platforms ranging from laptops to HPC systems.

Crosstalk Between Coplanar Waveguides Example: Views of the mesh boundaries for these two configurations are shown below. In both cases the computational domain is discretized using an unstructured tetrahedral mesh. 

[workshop] gdsfactory

gdsfactory workshop, UCSB Photonics Society

August 24, 2023 in Henley Hall, UCSB

The first gdsfactory hands-on workshop organized as part of the  UCSB  Photonics Society. Thomas Dorch from Freedom Photonics and Andrei Isichenko presented gdsfactory. Last year gdsfactory seminar by Joaquin Matres, the maintainer of gdsfactory - you can access the video recording here. This workshop was a hands on; things to do before the workshop

1. Install anaconda python 3 on your computer. If you don't have it installed, the links below are for miniconda, a "lightweight" version of anaconda. Windows: link. Mac: link (select if Intel or M1).
2. Download a Python IDE. Either Visual Studio Code or Pycharm. Personally I prefer VS Code
3. Download klayout. Windows: link. Mac: link (works on M1 mac, Ventura 13.4).

gdsfactory team will be running the tutorial using python notebooks (.ipynb). These can be run through JupyterLab, VS code (install this extension), or through Google Colab. You have the option to skip all the steps above and run the notebooks entirely in Google Colab (but with some limitations in klayout integration). You can try it out using this notebooks in this repository, focused on workshop_part1.ipynb. In Google Drive you should have the option to select "open with Google Colaboratory"

Click the "Open in Colab" link above to get started, and save a copy of the notebook to your Google Drive.

Google Drive Links to the notebooks:

https://drive.google.com/file/d/1x6kHQ9nHb1HB4HOEiEr1BG_y5lQ8si3e/view?usp=sharing

https://drive.google.com/file/d/1Ppz-CDrFezfLTIAHeBLYopl6Q4oyt8a4/view?usp=sharing

[Workshop] QIP

Silicon Quantum Information Processing (QIP) Workshop

Glasgow Marriott Hotel

Wednesday, Sept. 20, 2023

Silicon Quantum Information Processing (QIP) is highly appealing due to excellent spin qubit performances and the expertise of the integrated circuit industry in device scaling. Demonstrations of long-lived, high-fidelity silicon qubits, multi-qubit gates and spin–photon coupling, are promising for the control and interconnect of QIP architectures. Recently, spin qubits in related semiconductors (e.g. germanium) have also emerged as promising implementations of scalable quantum hardware. The formidable challenge of scaling these systems to the level required for meaningful computational applications has also brought to the fore the need for robust cryo-CMOS electronics, which will enable fast control and data processing, as well as schemes to correct errors and protect against decoherence. This meeting will bring together leading researchers from the QIP communities of silicon and related semiconductors, as well as cryo-CMOS designers and engineers who are working at different layers of the “quantum stack”.

10:00AM- 10:10AM	Introduction
10:10AM- 10:40AM	Pablo Cova Farina Quantum dot ladders for quantum computation and simulation
10:40AM-11:00AM	Federico Fedele Automatic techniques for fast and automatic all-rf tuning of quantum devices
11:00AM-11:30AM	Mark Johnson Rapid characterisation of over 1000 silicon quantum dots
11:30AM-11:50AM	Break and refreshments
11:50AM-12:20PM	Gian Salis How are hole-spin qubits in Ge/SiGe heterostructures driven and why do they decohere?
12:20PM-12:40PM	Ross Leon Exchange control in a MOS double quantum dot made on a 300mm process
12:40PM-1:10PM	Asen Asenov A Methodology for Cryogenic PDK Re-Centering Using Experimental Data and TCAD Simulations
1:10PM-2:30PM	Lunch
2:30PM-3:00PM	Masoud Babaie A Cryo-CMOS Receiver for Spin Qubit Gate-Based Readout: from Modelling to Implementation and Verification
3:00PM-3:20PM	Mathieu de Krujif Measurement of classical electronics heating a local quantum dot thermometer in silicon
3:20PM-3:40PM	Janne Lehtinen Custom CMOS platform for quantum processor units
3:40PM-4:00PM	Stavroula Kapoulea Towards the Development of Quantum Computing System-On-Chip: Bringing Electronics Closer to Qubits
4:00PM-4:10PM	Concluding remarks
4:10PM-5:00PM	Refreshments
5:00PM-6:00PM	Lab tour
7:00PM-9:00PM	Conference Dinner

[book] Advanced Ultra Low-Power Semiconductor Devices

Advanced Ultra Low-Power Semiconductor Devices

Design and Applications

Edited by Shubham Tayal, Abhishek Kumar Upadhyay, Shiromani Balmukund Rahi, and Young Suh Song

ISBN: 9781394166411 | (C)2023  Hardcover | 306 pages

Description

This outstanding new volume offers a comprehensive overview of cutting-edge semiconductor components tailored for ultra-low power applications. These components, pivotal to the foundation of electronic devices, play a central role in shaping the landscape of electronics. With a focus on emerging low-power electronic devices and their application across domains like wireless communication, biosensing, and circuits, this book presents an invaluable resource for understanding this dynamic field.

Bringing together experts and researchers from various facets of the VLSI domain, the book addresses the challenges posed by advanced low-power devices. This collaborative effort aims to propel engineering innovations and refine the practical implementation of these technologies. Specific chapters delve into intricate topics such as Tunnel FET, negative capacitance FET device circuits, and advanced FETs tailored for diverse circuit applications.

Beyond device-centric discussions, the book delves into the design intricacies of low-power memory systems, the fascinating realm of neuromorphic computing, and the pivotal issue of thermal reliability. Authors provide a robust foundation in device physics and circuitry while also exploring novel materials and architectures like transistors built on pioneering channel/dielectric materials. This exploration is driven by the need to achieve both minimal power consumption and ultra-fast switching speeds, meeting the relentless demands of the semiconductor industry. The books scope encompasses concepts like MOSFET, FinFET, GAA MOSFET, the 5-nm and 7-nm technology nodes, NCFET, ferroelectric materials, subthreshold swing, high-k materials, as well as advanced and emerging materials pivotal for the semiconductor industrys future.