Two-dimensional electron gas oxide remote doping of Si(001)

We demonstrate the integration of a two-dimensional electron gas (2DEG) oxide structure composed of $\mathrm{LaTi}{\mathrm{O}}₃/\mathrm{SrTi}{\mathrm{O}}₃$ (LTO/STO) on undoped Si(001) that possesses the attractive attributes of high charge density from the oxide and high mobility of silicon. Key to this approach is modification of the oxygen content at the STO-Si interface, which tunes the band alignment and induces electron carriers to move from the oxide 2DEG to form a 2DEG in the silicon substrate. As a consequence, the overall mobility of the heterostructure increases by two orders of magnitude compared to that in the oxide 2DEG to up to $100\phantom{\rule{0.28em}{0ex}}\mathrm{c}{\mathrm{m}}²{\mathrm{V}}^{\ensuremath{-}1}{\mathrm{s}}^{\ensuremath{-}1}$ at room temperature, with a carrier density of $\ensuremath{\sim}1\ifmmode\times\else\texttimes\fi{}{10}¹³\phantom{\rule{0.28em}{0ex}}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}2}$. This approach can be applied to technologies that require both high carrier and high carrier mobility for applications in plasmonics and high power electronics.