摘要:
An improved method for fabricating a NAND-type memory cell structure. The present invention forgoes providing a contact mask implantation process prior to deposition of a metal barrier layer, which is a typical order of processing the NAND-type memory cell. Instead, in the present invention, the metal barrier layer is deposited on a core area of the NAND-type memory cell prior to contact mask implantation. Thereafter, the contact mask implantation process is performed on the structure in a conventional manner.
摘要:
In a first aspect of the present invention, a method of fabricating a flash memory device is disclosed. The method comprises the steps of providing a portion of a dual gate oxide in a periphery area of the memory device and then simultaneously providing a dual gate oxide in a core area of the memory device and completing the dual gate oxide in the periphery area. Finally, a nitridation process is provided in both the core and periphery areas subsequent to the previous steps. In a second aspect of the present invention, a flash memory device is disclosed. The flash memory device comprises core area having a plurality of memory transistors comprising an oxide layer, a first poly layer, an interpoly dielectric layer, and a second poly layer. The flash memory device further comprises a periphery area having a plurality of transistors comprising an oxide layer, a portion of the first poly layer, and the second poly layer. According to the present invention, the method for fabricating the flash memory device is a simplified process that results in a significant improvement in the oxide reliability in the core and periphery areas and also eliminates the nitrogen contamination problem in the periphery area.
摘要:
A method of forming floating gate to improve tunnel oxide reliability for flash memory devices. A substrate having a source, drain, and channel regions is provided. A tunnel oxide layer is formed over the substrate. A floating gate is formed over the tunnel oxide and the channel region, the floating gate being multi-layered and having a second layer sandwiched between a first layer and a third layer. The first layer of the floating gate overlying the tunnel oxide layer includes an undoped or lightly doped material. The second layer is highly-doped. The third layer is in direct contact with a dielectric layer, e.g., an oxide-nitride-oxide stack, and is made of an undoped or lightly doped material. A dielectric material is formed over the floating gate and a control gate is formed over the dielectric material.
摘要:
Charge-trapping dielectric (160) in a nonvolatile memory cell is recessed from under the control gate's edge and/or from an edge of a substrate isolation region. The recessed geometry serves to reduce or eliminate charge trapping in regions from which the charge may be difficult to erase.
摘要:
A memory device having a cell stack and a select gate formed adjacent to the cell stack. The cell stack includes a first trap-free-nitride layer formed on a channel region of a substrate, a second nitride layer formed on the first nitride layer, an oxide layer formed on the second nitride layer, a control gate formed on the high-K oxide layer, and a poly spacer as the select gate formed adjacent to the control gate.
摘要:
A method is provided for erasing a memory cell having a substrate, a control gate, a floating gate, a source region and a drain region. The method includes pre-programming the memory cell to raise a threshold voltage of the memory cell to a first predetermined level, wherein pre-programming the memory cell does not include a verification process for ensuring that the threshold voltage of the memory cell has been raised to the first predetermined level. The memory cell may be erased to lower the threshold voltage of the memory cell to a second predetermined level.
摘要:
An exemplary sensing circuit comprises a first transistor connected to a first node, where a target memory cell has a drain capable of being connected to the first node through a selection circuit during a read operation involving the target memory cell. The sensing circuit further comprises a decouple circuit which is connected to the first transistor. The decouple circuit includes a second transistor having a gate coupled to a gate of the first transistor. The decouple circuit further has a decouple coefficient (N) greater than 1. The drain of the second transistor is connected at a second node to a reference voltage through a bias resistor. With the arrangement, the drain of the second transistor generates a sense amp input voltage at the second node such that the sense amp input voltage is decoupled from the first node.
摘要:
The present invention is a method for fabricating a memory device. In one embodiment, a first impurity concentration is deposited in a channel region of a memory device. A second impurity concentration, which overlies the first impurity concentration, is then created in the channel region. Finally, a memory array is fabricated upon the channel region. The memory array overlies the first impurity concentration and the second impurity concentration.
摘要:
This invention describes methods for producing gate oxide regions in periphery regions of semiconductor chips, wherein the gate oxide regions have improved electrical properties. The methods involve the deposition of a barrier layer over the periphery of the semiconductor chip to prevent the introduction of contaminating nitrogen atoms into the periphery during a nitridation step in the core region of the semiconductor chip. By preventing the contamination of the gate areas of the periphery, the gate oxide regions so produced have increased breakdown voltages and increased reliability. This invention describes methods for etching the barrier layers used to protect the periphery from tunnel oxide nitridation. Semiconductor devices made with the methods of this invention have longer expected lifetimes and can be manufactured with higher device density.
摘要:
The present invention provides an apparatus and method for a metal oxide semiconductor field effect transistor (MOSFET) fabricated to reduce short channel effects. The MOSFET includes a semiconductor substrate, a gate stack formed above the semiconductor substrate, a drain side sidewall spacer formed on a drain side of the gate stack, a source side sidewall spacer formed on a source side of the gate stack, and source and drain regions. The source region is formed in the semiconductor substrate on the source side, and is aligned by the source side sidewall spacer to extend an effective channel length between the source region and drain region. The drain region is formed on the drain side in the semiconductor substrate, and is aligned by drain side sidewall spacer to further extend the effective channel length.