Abstract:
A floating gate and fabrication method thereof. A semiconductor substrate is provided, on which an oxide layer, a first conducting layer, and a patterned hard mask layer having an opening are sequentially formed. A spacer is formed on the sidewall of the opening. A second conducting layer is formed on the hard mask layer. The second conducting layer is planarized to expose the surface of the patterned hard mask layer. The surface of the second conducting layer is oxidized to form an oxide layer. The patterned hard mask layer and the oxide layer and the first conducting layer underlying the patterned hard mask layer are removed.
Abstract:
A gate with dual gate dielectric layer and fabrication method thereof. A semiconductor substrate is provided, on which a dielectric layer and a patterned hard mask layer with an opening are sequentially formed. A spacer is formed on a sidewall of the opening. The semiconductor substrate is ion implanted, the spacer and the exposed dielectric layer are removed, and a gate oxide layer is formed on the bottom of the opening.
Abstract:
A method for fabricating a vertical nitride read-only memory (NROM) cell. A substrate having at least one trench is provided. A spacer is formed over the sidewall of the trench. Subsequently, ion implantation is performed on the substrate using the spacer as a mask to form doping areas as bit lines in the substrate near its surface and the bottom of the trench. Bit line oxides are formed over each of the doping areas. After the spacer is removed, a conformable insulating layer as gate dielectric is deposited on the sidewall of the trench and the surface of the bit line oxide. Finally, a conductive layer as a word line is deposited over the insulating layer and fills in the trench.
Abstract:
A method for fabricating a vertical nitride read-only memory (NROM) cell. A substrate having at least one trench is provided. A spacer is formed over the sidewall of the trench. Subsequently, ion implantation is performed on the substrate using the spacer as a mask to form doping areas as bit lines in the substrate near its surface and the bottom of the trench. Bit line oxides are formed over each of the doping areas. After the spacer is removed, a conformable insulating layer as gate dielectric is deposited on the sidewall of the trench and the surface of the bit line oxide. Finally, a conductive layer as a word line is deposited over the insulating layer and fills in the trench.
Abstract:
A floating gate and a fabricating method of the same. A semiconductor substrate is provided. A gate dielectric layer and a conducting layer are sequentially formed on the semiconductor substrate. A patterned hard mask layer having an opening is formed on the conducting layer, wherein a portion of the conducting layer is exposed through the opening. A spacer is formed on the sidewall of the opening. The patterned hard mask layer is removed. A conducting spacer is formed on the sidewall of the spacer. The exposed conducting layer and the exposed gate dielectric layer are sequentially removed.
Abstract:
A floating gate with multiple tips and a fabrication method thereof. A semiconductor substrate is provided, on which a patterned hard mask layer is formed, wherein the patterned hard mask layer has an opening. A gate dielectric layer and a first conducting layer with a first predetermined thickness are formed on the bottom of the opening. A spacer is formed on the sidewall of the opening. A conducting spacer is formed on the sidewall of the spacer. The first conducting layer is etched to a second predetermined thickness. A multi-tip floating gate is provided by the first conducting layer and the conducting spacer. A protecting layer is formed in the opening. The patterned hard mask layer, the gate dielectric layer, a portion of the protecting layer, and a portion of the first spacer are etched to expose the surface of the first conducting layer.
Abstract:
A stacked gate flash memory device and method of fabricating the same. A cell of the stacked gate flash memory device in accordance with the invention is disposed in a cell trench within a substrate and source and drain regions are formed in the same substrate side of the adjacent isolation trenches. Thus, the stacked gate flash memory device of the invention can achieve high integration of memory cells.
Abstract:
A method of fabricating a floating gate for a flash memory. An active region is formed on a semiconductor substrate. A first insulating layer, a first conductive layer and a masking layer are sequentially formed in the active region. A part of the masking layer is removed to form a first opening. A second conductive layer is formed to cover the masking layer and the bottom surface and sidewall of the first opening. A second insulating layer is formed on the second conductive layer to fill the first opening. An oxidation process is performed until the second conductive layer in contact with the second insulating layer over the masking layer is oxidized into a third insulating layer. The second and third insulating layers are removed to form a second opening. A fourth insulating layer fills in the second opening. The masking layer and the first conductive layer underlying the masking layer uncovered by the fourth insulating layer are removed.
Abstract:
A method for fabricating the control gate and floating gate of a flash memory cell. An active area is firstly formed on a semiconductor substrate, followed by the formation of a first insulating layer, a first conductive layer and a first masking layer. A first opening is then formed by partially removing the first masking layer, and a floating gate oxide layer is formed by oxidation. The remaining first masking layer is removed, followed by forming a sacrificial layer, which is then partially removed to define a second opening. The remaining sacrificial layer is used as a hard mask to partially remove the first conductive layer and the first insulating layer to form a third opening. A second insulating layer is formed to fill the third opening to form an insulating plug. Part of the first conductive layer and the first insulating layer are removed to form a floating gate, followed by forming a third insulating layer and a second conductive layer. The insulating plug is then used as stop layer to remove part of the second conductive layer and third insulating layer to form a control gate.
Abstract:
The present invention provides a process for fabricating a floating gate of a flash memory. First, an isolation region is formed in a semiconductor substrate and the isolation region has a height higher than the substrate. A gate oxide layer and a first polysilicon layer are then formed. The first polysilicon layer is formed according to the contour of the isolation region to form a recess in the first polysilicon layer. A sacrificial insulator is filled into the recess. The first polysilicon layer is then selectively removed in a self-aligned manner using the sacrificial insulator as a hard mask to expose the isolation region. A polysilicon spacer is formed on the sidewalls of the first polysilicon layer. A first mask layer is formed on the isolation region, the sacrificial insulator in the recess is removed, and a floating gate region is defined. Then, the surfaces of the first polysilicon layer and polysilicon spacer in the floating gate region are oxidized to form a polysilicon oxide layer. Finally, the polysilicon oxide layer is used as a mask to pattern the underlying first polysilicon layer and polysilicon spacer in a self-aligned manner to form a floating gate. During the oxidation process, the polysilicon spacer of the present invention serves as a buffer layer, which is oxidized and protects the floating gate from being oxidized. Thus, the floating gate and STI overlay, and current leakage caused by insufficient overlay is prevented.