Low on-resistance high-voltage lateral double-diffused metal oxide semiconductor with a buried improved super-junction layer

A novel low specific on-resistance (R_on,sp) lateral double-diffused metal oxide semiconductor (LDMOS) with a buried improved super-junction (BISJ) layer is proposed. A super-junction layer is buried in the drift region and the P pillar is split into two parts with different doping concentrations. Firstly, the buried super-junction layer causes the multiple-direction assisted depletion effect. The drift region doping concentration of the BISJ LDMOS is therefore much higher than that of the conventional LDMOS. Secondly, the buried super-junction layer provides a bulk low on-resistance path. Both of them reduce R_on,sp greatly. Thirdly, the electric field modulation effect of the new electric field peak introduced by the step doped P pillar improves the breakdown voltage (BV). The BISJ LDMOS exhibits a BV of 300 V and R_on,sp of 8.08 mΩ·cm² which increases BV by 35% and reduces R_on,sp by 60% compared with those of a conventional LDMOS with a drift length of 15 μm, respectively.