Abstract: A method for fabricating a transistor includes providing a substrate, having a gate region and a first trench in the substrate at a first side of the gate region; forming a first gate insulating layer, disposed on a first portion of the gate region, opposite to the first trench; forming a second gate insulating layer, disposed on a second portion of the gate region and a first portion of the first trench abutting to the gate region, wherein the second gate insulating layer is thicker than the first gate insulating layer; forming a gate layer, disposed on the first and second gate insulating layers, having a downward protruding portion corresponding to the first trench; forming a first doped region in the substrate at least under the first trench; and forming a second doped region in the substrate at a second side of the gate region.

Abstract: A method for fabricating a transistor includes providing a substrate, having a gate region and a first trench in the substate at a first side of the gate region; forming a first gate insulating layer, disposed on a first portion of the gate region, opposite to the first trench; forming a second gate insulating layer, disposed on a second portion of the gate region and a first portion of the first trench abutting to the gate region, wherein the second gate insulating layer is thicker than the first gate insulating layer; forming a gate layer, disposed on the first and second gate insulating layers, having a downward protruding portion corresponding to the first trench; forming a first doped region in the substrate at least under the first trench; and forming a second doped region in the substrate at a second side of the gate region.

Abstract: A transistor structure includes a substrate, having a gate region and a first trench in the substate at a first side of the gate region. Further, a first gate insulating layer is disposed on a first portion of the gate region, opposite to the first trench. A second gate insulating layer is disposed on a second portion of the gate region and a first portion of the first trench abutting to the gate region, wherein the second gate insulating layer is thicker than the first gate insulating layer. A gate layer is disposed on the first and second gate insulating layers, having a downward protruding portion corresponding to the first trench. A first doped region is in the substrate at least under the first trench. A second doped region is in the substrate at a second side of the gate region.

Abstract: A transistor structure includes a substrate, having a gate region and a first trench in the substrate at a first side of the gate region. Further, a first gate insulating layer is disposed on a first portion of the gate region, opposite to the first trench. A second gate insulating layer is disposed on a second portion of the gate region and a first portion of the first trench abutting to the gate region, wherein the second gate insulating layer is thicker than the first gate insulating layer. A gate layer is disposed on the first and second gate insulating layers, having a downward protruding portion corresponding to the first trench. A first doped region is in the substrate at least under the first trench. A second doped region is in the substrate at a second side of the gate region.

Abstract: A trapping gate forming process includes the following. An oxide/nitride/oxide layer is formed on a substrate. A hard mask is formed to cover the oxide/nitride/oxide layer. The hard mask, the oxide/nitride/oxide layer and the substrate are patterned to form at least a trench in the hard mask, the oxide/nitride/oxide layer along a first direction. An isolation structure is formed in the trench. A first gate is formed across the oxide/nitride/oxide layer along a second direction orthogonal to the first direction. A flash cell formed by said process includes a substrate, a first gate and an oxide/nitride/oxide layer. The substrate contains at least an active area extending along a first direction. The first gate is disposed across the active area along a second direction orthogonal to the first direction, thereby intersecting an overlapping area. The oxide/nitride/oxide layer is disposed in the overlapping area between the first gate and the active area.

Abstract: A trapping gate forming process includes the following. An oxide/nitride/oxide layer is formed on a substrate. A hard mask is formed to cover the oxide/nitride/oxide layer. The hard mask, the oxide/nitride/oxide layer and the substrate are patterned to form at least a trench in the hard mask, the oxide/nitride/oxide layer along a first direction. An isolation structure is formed in the trench. A first gate is formed across the oxide/nitride/oxide layer along a second direction orthogonal to the first direction. A flash cell formed by said process includes a substrate, a first gate and an oxide/nitride/oxide layer. The substrate contains at least an active area extending along a first direction. The first gate is disposed across the active area along a second direction orthogonal to the first direction, thereby intersecting an overlapping area. The oxide/nitride/oxide layer is disposed in the overlapping area between the first gate and the active area.