A 500-V High ON-BV Parasitic JFET With an Optimized Drift Region

A new 500-V ON-state breakdown voltage (ON-BV) parasitic JFET is proposed in this paper. Compared with traditional structures, a special junction field-effect transistor (JFET) region is located at the edge of the LDMOS. The drift region length of the JFET is larger than that of the LDMOS region. When JFET works in high-voltage on-state, the carriers are separated from the LDMOS region by a transition region close to the JFET region. Then the peak electric field and the impact ionization rate are suppressed. It helps the device to achieve the high ON-BV. Experimental results show that the ON-BV of the proposed structure is larger than 500 V, which is far larger than that of the traditional structures. In addition, the OFF-state breakdown voltage is 550 V.