Non-volatile memory transistor with nanotube floating gate
OwnerBohumil Lojekinventor
Life of this patent
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Abstract
Non-volatile memory transistors have a semiconductor substrate with spaced apart source and drain regions defining a channel, a layer of tunnel oxide over the channel and a conductive layer of carbon nanotubes over the tunnel oxide. In patterning, mesas are formed retaining desired locations of nanotubes as floating gates. The mesas are used for self-aligned implantation of source and drain electrodes. The nanotubes, being deposited as a porous randomly arranged matted layer, allow for etch removal of the support layer so that the nanotubes rest directly on tunnel oxide. The nanotubes are protected with insulative material and a conductive control gate is placed over the nanotube floating gate layer.
Claims15
A floating gate non-volatile memory transistor comprising,
- a semiconductor substrate having spaced apart source and drain electrodes in the substrate,
- a layer of tunnel oxide above the substrate between the source and drain,
- an electrically floating carbon nanotube web layer above the tunnel oxide, and
- a conductive layer over the carbon nanotube layer.
In a floating gate memory transistor of the type having a source and drain in a semiconductor substrate, tunnel oxide above the substrate between the source and drain, a floating gate above the tunnel oxide and a control gate in insulated relation above the floating gate, the improvement comprising,
- a plurality of carbon nanotubes embedded in insulative material forming the floating gate.
An intermediate structure for use in making non-volatile memory transistors comprising,
- a doped semiconductor wafer having a planar surface,
- a layer of tunnel oxide over the planar surface,
- a support layer over the tunnel oxide layer, and
- a carbon nanotube layer deposited over the support layer.
An intermediate structure for use in making non-volatile memory transistors comprising,
- a doped semiconductor wafer having a planar surface,
- a layer of tunnel oxide over the planar surface,
- a support layer over the tunnel oxide layer, and
- a layer of nanotube-forming catalyst deposited over the support layer.
Dependencies are inferred from the claim text.