Field oxide device with zener junction for electrostatic discharge protection and other applications

A field oxide device (FOD) for electrostatic discharge (ESD) protection and other applications, in which the field oxide device (FOD) is characterized in having lower breakdown voltage and with capability for controlling higher current during electrostatic discharge. The field oxide device (FOD) includes a zener junction to induce earlier breakdown of the device. The zener junction also provides a planar breakdown area having capability for controlling higher current. Especially, the field oxide device (FOD) comprises a p- doping substrate, in which the substrate has a drain-end n+ diffusion area and a source-end n+ diffusion area separated by a field oxide layer. The field oxide device (FOD) further comprises a p+ doping area, whose interface connecting with the drain-end n+ diffusion area forms a zener junction. The field oxide device (FOD) can be easily configured by controlling the doping density and energy of the p+ doping area. The field oxide device (FOD) further comprises one or more n+ areas on the boundary of the drain-end and source-end n+ diffusion area to provide an improved junction area ratio. Furthermore, the field oxide layer between the drain-end n+ diffusion and the source-end n+ diffusion regions, field oxides can be added respectively at the drain and source ends to provide isolation from other devices within an integrated circuit.