Manufacturing of high aspect-ratio p-n junctions using vapor phase doping for application in multi-Resurf devices

A new technique to manufacture vertical Resurf devices is presented, in which the alternating p-n junctions in the drift region are formed by a combination of trench etching and vapor phase doping (VPD). Scanning capacitance microscopy (SCM) was performed to investigate these deep p-n junctions, showing a uniform doping profile along the full depth of the devices. Electrical measurements on such Resurf diodes display an increase in breakdown voltage from 30 V to 145 V for a device with a 10 μm deep drift region doped at 3.5×10¹⁶ cm^-3. Such a concept leads to prediction of a specific on-resistance well below the silicon limit for an equivalent MOSFET.