Impact of La2O3/InGaAs MOS Interfaces on the Performance of InGaAs MOSFETs

The impact of La
₂
O
₃
/InGaAs MOS interfaces on the performance of InGaAs MOSFETs is systematically investigated. The low interface state density (D
_it
) of La
₂
O
₃
/InGaAs MOS interfaces is attributable to the formation of an intermixing layer between InGaAs and La
₂
O
₃
, which is rich in As
₂
O
₃
. The La
₂
O
₃
/InGaAs MOSFETs exhibit smaller subthreshold slope with the minimum value of 93 mV/dec than HfO
₂
/InGaAs MOSFETs and smaller carrier trapping properties than Al
₂
O
₃
/InGaAs and HfO
₂
/InGaAs MOSFETs. In the channel mobility analysis, it is found that La
₂
O
₃
/InGaAs MOSFETs have higher Coulomb scattering probability due to the higher oxide fixed charge density and resulting degradation of the channel mobility, while have smaller surface roughness than Al
₂
O
₃
/InGaAs MOSFETs.