A high-voltage semiconductor device includes a silicon substrate having a main surface, a gate on the main surface of the silicon substrate, a source region in a portion of the silicon substrate proximate the main surface and a drain region in a portion of the silicon substrate proximate the main surface. The drain region is spaced apart from the source region. A channel region is defined in a portion of the silicon substrate proximate the main surface between the source region and the drain region. The channel region is at least partially beneath the gate. An additional region is disposed on the main surface proximate the channel region. The additional region being formed of one of a high-k material and a conductive material.