Tunable diameter and spacing of double Ge quantum dots using highly-controllable spacers and selective oxidation of SiGe

Tsung Lin Huang, Kang Ping Peng, Ching Lun Chen, Horng Chih Lin, Tom George, Pei Wen Li*

*Corresponding author for this work

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

We report the novel tunability of the diameters and spacings of paired Ge double quantum dots (DQDs) using nano-spacer technology in combination with selective oxidation of Si0.85Ge0.15 at high temperature. Pairs of spherical-shaped Ge QDs were formed by the selective oxidation of poly-SiGe spacer islands at each sidewall corner of the nano-patterned Si3N4/poly-Si ridges. The diameters of the Ge spherical QDs are essentially determined by geometrical conditions (height, width, and length) of the nano-patterned spacer islands of poly-SiGe, which are tunable by adjusting the process times of deposition and etch back for poly-SiGe spacer layers in combination with the exposure dose of electron-beam lithography. Most importantly, the separations between the Ge DQDs are controllable by adjusting the widths of the poly-Si/Si3N4 ridges and the thermal oxidation times. Our self-organization and self-alignment approach achieved high symmetry within the Ge DQDs in terms of the individual QD diameters as well as the coupling barriers between the QDs and external electrodes in close proximity.

Original languageEnglish
Article number11303
JournalScientific reports
Volume9
Issue number1
DOIs
StatePublished - 5 Aug 2019

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