Method of forming semiconductor device with gate

A method for forming a semiconductor device, comprising:

• forming an isolation structure in a semiconductor substrate, wherein the isolation structure surrounds an active region of the semiconductor substrate;
• forming a gate over the semiconductor substrate, wherein the gate is across the active region and extends onto the isolation structure;
• depositing an insulating layer over the semiconductor substrate, the gate, and the isolation structure;
• removing a portion of the insulating layer over an intermediate portion of the gate and the active region to form a patterned insulating layer and to expose the intermediate portion and the active region, wherein the patterned insulating layer is over a first top surface and a sidewall of the gate and a second top surface of the isolation structure, the first top surface and the second top surface face away from the semiconductor substrate, the entire patterned insulating layer and an entire topmost surface of the active region do not overlap with each other, the topmost surface of the active region faces the gate, the patterned insulating layer has a first part and a second part, the first part is over the first top surface, the second part is over the second top surface, and the second part is between the first part and the isolation structure along an axis perpendicular to the second top surface;
• and
• after removing the portion of the insulating layer over the intermediate portion of the gate and the active region, forming lightly doped regions in the semiconductor substrate and at two opposite sides of the gate.

A method for forming a semiconductor device, comprising:

• forming an isolation structure in a semiconductor substrate, wherein the isolation structure surrounds an active region of the semiconductor substrate;
• forming a gate over the semiconductor substrate, wherein the gate is across the active region and extends onto the isolation structure, the gate has an intermediate portion and a first end portion, the intermediate portion is over the active region, and the first end portion is over the isolation structure;
• forming a support film over the isolation structure and the first end portion, wherein the support film continuously covers a first top surface and a first sidewall of the first end portion and a second top surface of the isolation structure, the first top surface and the second top surface face away from the semiconductor substrate, the support film is spaced apart from the active region, a portion of the support film covering the gate has an inverted U shape in a cross-sectional view of the support film and the gate, the support film has a first part and a second part, the first part is over the first top surface, the second part is over the second top surface, a first distance between a third top surface of the first part and the second top surface of the isolation structure is greater than a second distance between a fourth top surface of the second part and the second top surface of the isolation structure, and the first distance and the second distance are measured along an axis perpendicular to the second top surface;
• and
• after forming the support film, forming lightly doped regions in the semiconductor substrate and at two opposite sides of the gate.