High voltage semiconductor device and method of manufacturing same

A high voltage semiconductor device comprising:

• a semiconductor layer or substrate;
• a gate structure on the semiconductor layer or substrate;
• a slope compensating structure on an outermost surface of the gate structure;
• an insulating pattern on the gate structure and the slope compensating structure;
• and
• a gate field plate on the insulating pattern,
• wherein the gate structure comprises a gate insulating film on the semiconductor layer or substrate;
• a gate electrode on the gate insulating film;
• and a gate spacer on a sidewall of the gate electrode,
• the gate spacer has an outermost surface that comprises a first portion, which is curved, and a second portion extending downward from the first portion with a steeper slope than the first portion,
• the slope compensating structure has an outermost surface with a gentler slope than that of the second portion, and the slope compensating structure does not overlap the first portion laterally and is surrounded by the semiconductor layer or substrate, the insulating pattern, and the gate spacer, and
• each of the slope compensating structure, the insulating pattern, and the gate spacer contacts the semiconductor layer or substrate.