摘要:
A P-type dopant is implanted into a substrate region 94 under a select drain gate transistor field oxide region 75 at a large tilt angle .alpha., to prevent field turn-on under the select drain gate transistor field oxide region 75 in a non-volatile memory device such as a NAND flash memory device. A substrate region 114 under a select source gate transistor field oxide region 77 can also be implanted with a P-type dopant to prevent field turn-on under the region 77 if select source gates 90 and 92 are to be supplied with a voltage in operation rather than grounded. The substrate regions 94 and 114 under both the select drain gate transistor field oxide region 75 and the select source gate transistor field oxide region 77 can be implanted with the P-type dopant using a fixed-angle ion beam 120, by rotating the wafer 124 between the step of implanting one of the substrate regions and the step of implanting the other region.
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:
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:
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.
摘要:
A memory device includes a cell stack and a select gate formed adjacent to the cell stack. The cell stack includes a tunneling dielectric layer, a charge storage layer, a blocking dielectric layer, and a control gate. Applying a positive bias to the control gate, the select gate and the source of the device injects negative charges from a channel region of a substrate by hot electron injection through the tunneling dielectric layer at a location near a gap between the select gate and the control gate into the charge storage layer to store negative charges in the charge storage layer. Applying a negative bias to the control gate directly tunnels positive charges from the channel region of the substrate through the tunneling dielectric layer and into the charge storage layer to store positive charges in the charge storage layer.