Stable breakdown characteristics of 600 V LDMOS by extended P-bottom region

A new LDMOS promising stable hard breakdown characteristics by releasing the crowded electric field at the gate oxide edge is proposed. Extending P-bottom into the n-drift region can stabilize the breakdown characteristics of LDMOS. The numerical calculations and experimental results have shown that a stable breakdown voltage of over 600 V can be obtained when enclosed P-bottom width to P-well is 10 /spl mu/m and a P-top dose of 1/spl times/10/sup 12/ cm/sup -2/ is used.