Temperature Dependence of the Threshold Voltage Shift Induced by Carrier Injection in Integrated STI-Based LDMOS Transistors

Large threshold voltage shifts (Δ
Vt
) are experimentally observed in n-channel lateral DMOS transistors under high current-voltage regime. The effect is enhanced by the gate voltage as well as by the ambient temperature (
TA
) . By approximating the curves with the usually adopted power-law dependence (Δ
Vt
=
Atn
), two different contributions are observed, and a clear increase of the exponent
n
is found. A numerical investigation is carried out, revealing that the electric field normal to the oxide interface (
En
) as well as the internal temperature (
T
) close to the source side of the MOS channel is mainly responsible for such enhanced degradation.