Lateral power integrated devices having low on-resistance

A lateral power integrated device includes a source region and a drain region disposed in a semiconductor layer and spaced apart from each other in a first direction, a drift region disposed in the semiconductor layer and surrounding the drain region, a channel region arranged between the source region and the drift region in the first direction, a plurality of planar insulation field plates disposed over the drift region and spaced apart from each other in a second direction, a plurality of trench insulation field plates disposed in the drift region, a gate insulation layer formed over the channel region, and a gate electrode formed over the gate insulation layer. Each of the trench insulation field plates is disposed between the planar insulation field plates in the second direction.