A sensor-type semiconductor package and a fabrication method thereof are provided. The drift region comprises first and second portions, the first portion extending partially under a gate structure between the channel and the second portion, and the second portion extending laterally between the first portion and the drain, wherein the first portion of the drift region has a concentration of first type dopants higher than the second portion. The housing sections define an internal cavity that is dimensioned to hold the valve assembly in an opened position.