Abstract
GeSn N-MOSFETs fabricated on GeSn (Sn~4.5 %) formed by solid phase epitaxy (SPE) with GeSnOx passivation layer grown by O2 plasma were investigated in this work. The major advances compared to prior arts lie in two aspects. (1) epitaxial GeSn film by SPE has drawn intense interest due to relatively simple process with lower cost. However, only P-MOSFETs were reported on GeSn film by SPE. This is the first demonstration showing that SPE is also an eligible technique to empower high-performance GeSn N-MOSFETs. (2) O2 plasma for GeSnOx passivation layer growth can be integrated into the same ALD tool for high-κ dielectric deposition, making the process simpler. More importantly, besides the cost-effective process to implement GeSn N-MOSFETs, the devices exhibit high peak electron mobility exceeding 500 cm2/Vs which outperforms the data reported in the literature and can be ascribed to high quality of the epitaxial GeSn film as well as the effective surface passivation.