Published online by Cambridge University Press: 17 July 2013
Nitridation of GeO2 interfacial layer (IL) was done using continuous wave (CW) and pulsed wave (PW) decoupled plasma nitridation (DPN) processes. Langmuir probe analysis of the N2 plasma demonstrates that at the same effective power and pressure, PW plasma has similar electron density (Ne) with lower electron temperature (kTe) and plasma potential (Vp) as compared to CW plasma. This results in softer plasma conditions using a PW process leading to lower plasma-related damage in the IL, but without reducing the overall nitrogen concentration. The plasma parameters were further correlated to mobility (μ) and interface trap density (Dit) extracted from fabricated Ge n-MOSFETs. As expected from the plasma analysis, at the same effective power and pressure, the PW DPN process shows 1.2X higher electron mobility as compared to a CW process. This improvement can enable GeON as an IL for future Ge CMOS gate stack technology.