A high voltage metal-oxide-metal (HV-MOM) device includes a substrate, a deep well in the substrate and at least one high voltage well in the substrate over the deep well. The HV-MOM device further includes a dielectric layer over each high voltage well of the at least one high voltage well and a gate structure over the dielectric layer. The HV-MOM device further includes an inter-layer dielectric (ILD) layer over the substrate, the ILD layer surrounding the gate structure. The HV-MOM device further includes a first inter-metal dielectric (IMD) layer over the ILD layer and a first metal feature in the first IMD layer, wherein the first metal feature is part of a MOM capacitor.