Temperature-Dependent Electrical Properties of nMOSFETs With Different Thickness Al₂O₃ Capping Layer and TiN Gate

In this article, the electrical properties of nMOSFET devices with different high-
${k}$
Al
₂
O
₃
capping layer thickness and TiN electrode have been systematically studied at deep cryogenic temperatures ranging from 10 to 300 K. The threshold voltage
${V}_{\text {TH}}$
, transconductance
${g}_{m}$
, carrier mobility
$\mu $
, mobility attenuation factor
$\theta $
, and subthreshold swing (SS) are extracted using the
${I}_{\text {DS}}$
–
${V}_{\text {GS}}$
curves and Y-function method at different temperatures. It is indicated that: 1) all the electrical parameters (
${V}_{\text {TH}}$
,
${g}_{m}$
,
$\mu $
,
$\theta $
, and SS) show strong temperature dependence in the range of studied temperatures and 2) temperature-dependent electrical properties of nMOSFET devices will modulate at various cryogenic temperatures ascribed to the presence of the Al
₂
O
₃
capping layer on the SiO
₂
dielectric layer, which increases the oxide trap density and consequentially adjusts the threshold voltage and mobility of the devices.