Abstract: A semiconductor device includes a semiconductor substrate, a trench, and a gate structure. The trench is disposed in the semiconductor substrate. The gate structure is disposed on the semiconductor substrate. The gate structure includes a gate electrode, a first gate oxide layer, and a second gate oxide layer. A first portion of the gate electrode is disposed in the trench, and a second portion of the gate electrode is disposed outside the trench. The first gate oxide layer is disposed between the gate electrode and the semiconductor substrate. At least a portion of the first gate oxide layer is disposed in the trench. The second gate oxide layer is disposed between the second portion of the gate electrode and the semiconductor substrate in a vertical direction. A thickness of the second gate oxide layer is greater than a thickness of the first gate oxide layer.

Abstract: A semiconductor device includes a semiconductor substrate, a gate structure, a first drift region, a first source/drain region, and a gate oxide layer. The gate structure and the gate oxide layer are disposed on the semiconductor substrate. The first drift region is disposed in the semiconductor substrate. The first source/drain region is disposed in the first drift region. At least a part of a first portion of the gate oxide layer is disposed between the gate structure and the semiconductor substrate in a vertical direction. A second portion of the gate oxide layer is disposed between the first portion and the first source/drain region in a horizontal direction. The second portion includes a bottom extending downwards and a first depressed top surface located above the bottom. A part of the first drift region is located under the first portion and the second portion of the gate oxide layer.

Abstract: A semiconductor device includes a semiconductor substrate, a trench, and a gate structure. The trench is disposed in the semiconductor substrate. The gate structure is disposed on the semiconductor substrate. The gate structure includes a gate electrode, a first gate oxide layer, and a second gate oxide layer. A first portion of the gate electrode is disposed in the trench, and a second portion of the gate electrode is disposed outside the trench. The first gate oxide layer is disposed between the gate electrode and the semiconductor substrate. At least a portion of the first gate oxide layer is disposed in the trench. The second gate oxide layer is disposed between the second portion of the gate electrode and the semiconductor substrate in a vertical direction. A thickness of the second gate oxide layer is greater than a thickness of the first gate oxide layer.

Abstract: A semiconductor device includes a semiconductor substrate, a gate structure, a first drift region, a first source/drain region, and a gate oxide layer. The gate structure and the gate oxide layer are disposed on the semiconductor substrate. The first drift region is disposed in the semiconductor substrate. The first source/drain region is disposed in the first drift region. At least a part of a first portion of the gate oxide layer is disposed between the gate structure and the semiconductor substrate in a vertical direction. A second portion of the gate oxide layer is disposed between the first portion and the first source/drain region in a horizontal direction. The second portion includes a bottom extending downwards and a first depressed top surface located above the bottom. A part of the first drift region is located under the first portion and the second portion of the gate oxide layer.

Abstract: A method for forming alignment keys of a semiconductor structure includes: forming an oxide pad layer and a passivation layer on a substrate; forming a patterned photoresist layer on the passivation layer, and using the patterned photoresist layer as a mask to remove part of the oxide pad layer and passivation layer and expose the substrate surface in the medium voltage and alignment mark regions; forming oxide portions on the exposed substrate surface, and the oxide portions extending into the first depth of the substrate; forming deep doped wells in the low voltage and medium voltage regions; thinning the oxide portions; forming high-voltage doped wells in the high voltage and alignment mark regions; performing an etching process on the high voltage and alignment mark regions to form a second trench, as an alignment key, having a second depth greater than the first depth in the alignment mark region.

Abstract: A semiconductor device includes a semiconductor substrate, a gate structure, a first drift region, a first source/drain region, and a gate oxide layer. The gate structure and the gate oxide layer are disposed on the semiconductor substrate. The first drift region is disposed in the semiconductor substrate. The first source/drain region is disposed in the first drift region. At least a part of a first portion of the gate oxide layer is disposed between the gate structure and the semiconductor substrate in a vertical direction. A second portion of the gate oxide layer is disposed between the first portion and the first source/drain region in a horizontal direction. The second portion includes a bottom extending downwards and a first concave top surface located above the bottom. A part of the first drift region is located under the first portion and the second portion of the gate oxide layer.

Abstract: A semiconductor device includes a semiconductor substrate, a trench, and a gate structure. The trench is disposed in the semiconductor substrate. The gate structure is disposed on the semiconductor substrate. The gate structure includes a gate electrode, a first gate oxide layer, and a second gate oxide layer. A first portion of the gate electrode is disposed in the trench, and a second portion of the gate electrode is disposed outside the trench. The first gate oxide layer is disposed between the gate electrode and the semiconductor substrate. At least a portion of the first gate oxide layer is disposed in the trench. The second gate oxide layer is disposed between the second portion of the gate electrode and the semiconductor substrate in a vertical direction. A thickness of the second gate oxide layer is greater than a thickness of the first gate oxide layer.

Abstract: A semiconductor structure includes a substrate having a first region and a second region around the first region. A first fin structure is disposed within the first region. A second fin structure is disposed within the second region. A first isolation trench is disposed within the first region and situated adjacent to the first fin structure. A first trench isolation layer is disposed in the first isolation trench. A second isolation trench is disposed around the first region and situated between the first fin structure and the second fin structure. The bottom surface of the second isolation trench has a step height. A second isolation layer is disposed in the second isolation trench.

Abstract: A manufacturing method a semiconductor device includes the following steps. A first mask pattern and a second mask pattern are formed on a first region and a second region of a substrate respectively. The second region is located adjacent to the first region. A top surface of the first mask pattern is lower than a top surface of the second mask pattern in a thickness direction of the substrate. A trench is formed in the substrate. The trench is partly located in the first region and partly located in the second region. A first etching process is performed for reducing a thickness of the second mask pattern and reducing a height difference between the top surface of the first mask pattern and the top surface of the second mask pattern in the thickness direction of the substrate. An isolation structure is formed in the trench after the first etching process.

Abstract: A semiconductor structure includes a substrate having a first region and a second region around the first region. A first fin structure is disposed within the first region. A second fin structure is disposed within the second region. A first isolation trench is disposed within the first region and situated adjacent to the first fin structure. A first trench isolation layer is disposed in the first isolation trench. A second isolation trench is disposed around the first region and situated between the first fin structure and the second fin structure. The bottom surface of the second isolation trench has a step height. A second isolation layer is disposed in the second isolation trench.