QUANTUM TECHNOLOGY

TSV Plasma Polish optimization and AFM characterization for Quantum Computing

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Superconducting through-silicon vias (TSVs) are critical components for building scalable superconducting quantum computing (SQC) platforms. By incorporating TSVs, we can significantly increase the number of qubits, achieve higher integration densities, and enhance coherence times, which are all essential for advancing quantum computing technologies. Among materials for superconducting applications, niobium nitride (NbN) is an excellent choice due to its high critical temperature (Tc), making it particularly suitable for applications beyond the ultra-low temperatures of dilution refrigerators. 

To fabricate high-quality TSVs, we employed the Bosch process, which enabled us to achieve via depths greater than 300 µm. To optimize the surface quality, we further applied a dry plasma etching technique to reduce interface roughness. Sidewall roughness was measured using Atomic Force Microscopy (AFM), which confirmed that these processes yielded smooth, high-quality surfaces ideal for quantum applications.

In this presentation, Dr Ren will outline the methods used in the fabrication of superconducting quantum devices, with a focus on surface preparation techniques and superconductivity testing results. Additionally, Dr Kocun will introduce AFM instrumentation (Asylum Research Jupiter XR), AFM methods, and will define the key considerations regarding surface roughness measurements.

You will learn:

  • Latest advances in plasma polishing
  • Superconducting quantum computing and through silicon vias (TSV)
  • AFM characterization of sidewall roughness
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01 April 2025
Time:

4 : 00 PM (BST)

Duration:

1 hour

Language:

English

Businesses:

Asylum Research, Plasma Technology

Agenda

Time (GMT)

Talk Title

Presenter

16:00-16:05

Introduction to the webinar

Grant Baldwin

16:05-16:35

Methods used in the fabrication of superconducting quantum devices

Zhong Ren

16:35-16:50

Introduction of AFM instrumentation and methods

Marta Kocun

16:50-17:00

Q&A

Abstracts

Bias-Pulsed Atomic Layer Etching of Wide Bandgap Semiconductors
Julian Michaels, University of Illinois

Plasma Atomic Layer Etching (ALE) offers unparalleled precision when etching semiconductor material because it removes single atomic layers in each controlled etch cycle; however, the regular purging of reagent gases substantially slows its etch rate, limiting the widespread applicability of ALE processing. Bias-Pulsed Atomic Layer Etching (BP-ALE) offers the same level of atomic precision as conventional ALE at approximately ten times the speed. It eliminates the purging steps in a cycle and instead relies solely on pulsing the plasma DC bias. BP-ALE has been applied to a variety of wide bandgap semiconductors and has been shown to smooth the etched surface significantly through atomic force microscopy. This talk overviews BP-ALE, highlighting its differences to ALE, and seeks to predict the future materials for which it is compatible.


Using atomic layer deposition and etching for surface smoothing in 3D
Nicholas Chittock, Eindhoven University of Technology

As nanoelectronics pushes towards ever smaller technology nodes, control of surfaces and interfaces becomes increasingly important. One way to control the surface quality is to implement atomic layer deposition (ALD) and etching (ALE), where smoothing has been observed experimentally. However, the mechanism which drives smoothing was not understood for both ALD and ALE. In this talk we will discuss a model developed to predict the rate of smoothing for ALD and ALE of Al2O3, showing good agreement with experimental data and elucidating the mechanism by which smoothing occurs. By studying surface smoothing from ALD and ALE interesting avenues for combined processing became apparent, which enabled smoother films than can be achieved by either technique individually.

Speakers

Dr Zhong Ren - Oxford Instruments Plasma Technology
Principal Applications Engineer

Dr Zhong Ren received his PhD degree in photonics from the University of Bristol in 2008. After that he worked on compound semi...

Dr Marta Kocun - Oxford Instruments Asylum Research
Senior Applications Scientist

Dr Marta Kocun has a PhD in Biophysics from University of Goettingen, Germany where her studies focused on investigating mechan...


 
 

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