Linear Drain Current Degradation of ps-LDMOS Transistor Under ${\rm I}_{\rm submax}$ and ${\rm I}_{\rm gmax}$ Stress

The linear drain current (I
_dlin
) degradations of the p-type symmetric lateral double diffused MOS (ps-LDMOS) transistor under the maximum substrate current (I
_submax
) and the maximum gate current (I
_gmax
) stresses are experimentally investigated for the first time. For the stress time , the I
_dlin
increase under the I
_gmax
stress is faster than that under I
_submax
stress because of more serious hot-electron injection happening at the bird's beak of source region, and the degradation mechanism and damage position are very different from that of the unsymmetric LDMOS. However, for the stress time longer than 1000 s, the I
_dlin
begins to decrease under the I
_gmax
stress resulting from the interface state dominating the degradation of channel region, whereas the I
_dlin
still keeps increasing under the I
_submax
stress because of the continuous hot-electron injection into the field oxide of drain drift region.