Experimental Study of Ultralow On-resistance Power LDMOS with Convex-shape Field Plate Structure

An accumulation-mode LDMOS with convex-shape field plate (CFP ALDMOS) is proposed and experimentally investigated. The proposed CFP ALDMOS features convex field plate structures on source and drain side, wherein the contact regions and two back-to-back diodes (D1 and D2) are formed. In the on-state, a continuous electron accumulation layer is formed in the N-drift surface to decrease the specific on-resistance (R
on,sp
). In the off state to maintain the same breakdown voltage (BV) level, the CFP ALDMOS shrinks the drift length (L
D
), so as to achieve a dramatical lower R
on,sp
. The proposed CFP ALDMOS experimentally realizes R
on,sp
of 22.2 mΩ•cm
²
with BV of 489V. Its R
on,sp
is 48.4% and 51.1% lower than that of regular field plate (RFP) ALDMOS and triple-RESURF LDMOS under the same BV.