Enriching and purifying silicon epilayers for quantum information
Joshua M. Pomeroy, Kevin J. Dwyer, Ke Tang, Hyun Soo Kim, Aruna N. Ramanayaka, David S. Simons
High quality, enriched silicon contains an exceptionally low density of defects and unpaired electron and nuclear spins that allow candidate qubits (single donors or quantum dots) to exhibit very long dephasing times compared to silicon with a natural abundance of isotopes. Unfortunately, high quality enriched silicon is not a readily available resource. Only a few niche supplies exist and the advancement of silicon based quantum information is limited by access to these. As quantum information has made progress, efforts to increase supply have been made, but these are also hampered by sparse evidence for determining what level of enrichment is sufficient for eliminating the effects of nuclear spin dephasing. In this talk, I will describe very highly enriched silicon films that are grown epitaxially on Si(100) substrates. We have been refining the quality of these films with the aim of experimentally determining the relationship between important metrics, like coherence time, and the physical mechanisms limiting them, like nuclear spin density or chemical impurity density. At present, we have suppressed the minor isotope fraction in these films to ≈10-7, grown the films epitaxially with high crystalline quality and are successively reducing contaminant densities (mostly light gas components.) As the quality of the films has improved, we have begun making electronic test devices from this silicon, in particular, diodes, capacitors and transistors on the way to realizing single and multiple quantum dot devices.
ISDRS 2016 PROCEEDINGS
December 7-9, 2016
International Semiconductor Device Research Symposium
, Dwyer, K.
, Tang, K.
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, Ramanayaka, A.
and Simons, D.
Enriching and purifying silicon epilayers for quantum information, ISDRS 2016 PROCEEDINGS, Bethesda, MD
(Accessed October 22, 2021)