Hole Mobility Enhancement of GeSn/Ge pMOSFETs with an Interlayer Formed by Sn-Assisted Oxynitridation

Abstract

The GeSn/Ge pMOSFETs with a novel GeSnON interlayer formed by the Sn-assisted oxynitridation method were demonstrated and analysed. The introduced GeSn layer onto the Ge substrates enables the nitridation process to be performed at low temperatures. The oxynitridation of the GeSn layer can further improve the interface properties of GeSn/Ge MOS capacitors compared with the direct nitridation method. The fabricated GeSn/Ge pMOSFETs with the GeSnON interlayer exhibit more than 4 times hole mobility enhancement over Si universal mobility. The effective passivation of the GeSnON interlayer and the GeSn layer in channel region may account for the hole mobility enhancement.