Screening of remote charge scattering sites from the oxide/silicon interface of strained Si two-dimensional electron gases by an intermediate tunable shielding electron layer

Chiao Ti Huang, Jiun Yun Li, Kevin S. Chou, James C. Sturm

Research output: Contribution to journalArticle

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Abstract

We report the strong screening of the remote charge scattering sites from the oxide/semiconductor interface of buried enhancement-mode undoped Si two-dimensional electron gases (2DEGs), by introducing a tunable shielding electron layer between the 2DEG and the scattering sites. When a high density of electrons in the buried silicon quantum well exists, the tunneling of electrons from the buried layer to the surface quantum well can lead to the formation of a nearly immobile surface electron layer. The screening of the remote charges at the interface by this newly formed surface electron layer results in an increase in the mobility of the buried 2DEG. Furthermore, a significant decrease in the minimum mobile electron density of the 2DEG occurs as well. Together, these effects can reduce the increased detrimental effect of interface charges as the setback distance for the 2DEG to the surface is reduced for improved lateral confinement by top gates.

Original languageEnglish (US)
Article number4884650
JournalApplied Physics Letters
Volume104
Issue number24
DOIs
StatePublished - Jun 16 2014

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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