A Novel Planar Power MOSFET With Laterally Uniform Body and Ion-Implanted JFET Region

A novel sub-20-V planar power MOSFET using ion implantation to form the body and JFET regions is proposed and experimentally demonstrated. The fabricated novel device has a breakdown voltage of 14 V and a threshold voltage of 0.57 V. Compared with conventional planar vertical double-diffused MOS devices, the specific on-resistance of the novel device is reduced by 32% because of the reduced JFET resistance. The threshold- voltage variation of the novel device is also characterized. The standard deviation of the threshold voltage is reduced from 36 mV of the conventional device to 10 mV of the novel device. This is because the channel region of the novel device is uniformly doped by using ion implantation. The gate-drain charge density is similar to that of the conventional device. The novel device is very promising for sub-20-V dc/dc conversion applications.