Investigation of Kirk-Effect Induced Hot-Carrier-Injection in High-Voltage Power Devices

Hot-carrier-injection (HCI) effect is expected to well correlate with substrate current
$(\mathrm{I}_{\mathrm{SUB}})$
. However, in high-voltage (HV) device which features extended lightly-doped drain region (Ndrift), two
$\mathrm{I}_{\mathrm{S}\mathrm{U}\mathrm{B}}$
peaks are frequently observed and found to have different HCI degradation. Our data showed that the worst-case HCI after long term stress doesn't necessarily occur at largest
$\mathrm{I}_{\mathrm{S}\mathrm{U}\mathrm{B}}$
which is usually found at full V
G
operation due to Kirk-effect. The HCI dependence on
$\mathrm{I}_{\mathrm{S}\mathrm{U}\mathrm{B}}$
peak location in HV device is further investigated through TCAD simulation. Our study proved the changes in impact ionization location under 2
^nd
$\mathrm{I}_{\mathrm{S}\mathrm{U}\mathrm{B}}$
peak by Kirk-effect, thus leads to less
$\mathrm{Id}_{\mathrm{lin}}$
degradation in long term stress. Nit generation at pinch-off point is found to alter IIG (impact-ionization generation) location at HV high resistance drift region and could be explained through IIG simulation by TCAD.