$Si∕SiGe$ $n$-type resonant tunneling diodes fabricated using in situ hydrogen cleaning

In situ hydrogen cleaning to reduce the surface segregation of $n$-type dopants in SiGe epitaxy has been used to fabricate $Si∕SiGe$ resonant tunneling diodes in a joint gas source chemical vapor deposition and molecular beam epitaxial system. Diodes fabricated without the in situ clean demonstrate linear current-voltage characteristics, while a $15min$ hydrogen clean produces negative differential resistance with peak-to-valley current ratios up to 2.2 and peak current densities of $5.0A∕cm2$ at $30K$⁠. Analysis of the valley current and the band structure of the devices suggest methods for increasing the operating temperature of $Si∕SiGe$ resonant tunneling diodes as required for applications.