Patent ID: 8241978

Claim:
A method of manufacturing semiconductor device having integrated MOSFET and Schottky diode, comprising steps of: providing a semiconductor substrate having a first dopant type, the semiconductor substrate including a first surface and an opposite second surface, and the first surface having a MOSFET region and a Schottky diode region defined thereon; forming a plurality of first trenches in the MOSFET region, a plurality of second trenches and a plurality of mesas defined by the second trenches in the Schottky diode region of the first surface, a depth and a width of the second trenches are larger than a depth and a width of the first trench; forming a first insulating layer covering bottoms and sidewalls of the first trenches and the second trenches in the first surface; forming a first conductive layer filling the first trenches in the first surface; removing the first conductive layer from the first surface and from the second trenches to form a trenched gate in each first trench in the MOSFET region and to expose the first insulating layer in the second trenches in the Schottky diode region; forming a second insulating layer covering the bottom and sidewalls of the second trenches and the first surface, a thickness of the second insulating layer is larger than a thickness of the first insulating layer; forming a second conductive layer filling the second trenches on the first surface; forming an inter-layer dielectric (ILD) layer on the first surface; forming at least a source opening in the ILD layer and the semiconductor substrate in the MOSFET region; forming a first contact plug in the source opening; and forming a first metal layer on the first surface of the semiconductor substrate, the first metal layer being electrically connected to the first contact plug.