US6066869A — Circuit and method for a folded bit line memory c…

Claim 1

Independent Claim 139 words

A memory cell for a memory array in a folded bit line configuration, the memory cell comprising: an access transistor formed in a pillar of single crystal semiconductor material, the transistor having first and second source/drain regions and a body region that are vertically aligned; the access transistor further including a gate coupled to a word line disposed adjacent to only one side of the body region; a passing word line separated from the gate by an insulator for coupling to other memory cells adjacent to the memory cell; and a trench capacitor, wherein the trench capacitor includes a first plate that is formed integral with the second source drain region of the access transistor and a second plate that is disposed adjacent to and surrounding the first plate and separated from the first plate by a gate oxide.

Claim 2

Dependent Claim 139 words

A memory cell for a memory array in a folded bit line configuration, the memory cell comprising: an access transistor formed in a pillar of single crystal semiconductor material, the transistor having first and second source/drain regions and a body region that are vertically aligned; the access transistor further including a gate coupled to a word line disposed adjacent to only one side of the body region; a passing word line separated from the gate by an insulator for coupling to other memory cells adjacent to the memory cell; and a trench capacitor, wherein the trench capacitor includes a first plate that is formed integral with the second source drain region of the access transistor and a second plate that is disposed adjacent to and surrounding the first plate and separated from the first plate by a gate oxide.

Claim 3

Dependent Claim 12 words

The memory cell of claim 1, wherein the second plate comprises poly-silicon.

Claim 4

Dependent Claim 23 words

The memory cell of claim 1, and further comprising an ohmic contact that couples the second plate to a layer of semiconductor material.

Claim 5

Dependent Claim 169 words

A memory device, comprising: an array of memory cells, each cell including a vertical access transistor formed of a single crystalline semiconductor pillar that extends outwardly from a substrate with body and first and second source/drain regions, a gate disposed adjacent to only one side of the pillar adjacent to the body region and a trench capacitor wherein a first plate of the trench capacitor is integral with the second source/drain region and a second plate of the capacitor is disposed adjacent to and surrounding the first plate; a number of bit lines that are each selectively coupled to a number of the memory cells at the first source/drain region of the access transistor so as to fonn columns of memory cells in a folded bit line configuration; and a number of word lines disposed substantially orthogonal to the bit lines in trenches between rows of the memory cells, wherein each trench includes two word lines, each word line coupled to alternating gates on opposite sides of the trench.

Claim 6

Dependent Claim 169 words

A memory device, comprising: an array of memory cells, each cell including a vertical access transistor formed of a single crystalline semiconductor pillar that extends outwardly from a substrate with body and first and second source/drain regions, a gate disposed adjacent to only one side of the pillar adjacent to the body region and a trench capacitor wherein a first plate of the trench capacitor is integral with the second source/drain region and a second plate of the capacitor is disposed adjacent to and surrounding the first plate; a number of bit lines that are each selectively coupled to a number of the memory cells at the first source/drain region of the access transistor so as to fonn columns of memory cells in a folded bit line configuration; and a number of word lines disposed substantially orthogonal to the bit lines in trenches between rows of the memory cells, wherein each trench includes two word lines, each word line coupled to alternating gates on opposite sides of the trench.

Claim 7

Dependent Claim 18 words

The memory device of claim 4, wherein the pillars extend outwardly from a semiconductor portion of the substrate.

Claim 8

Dependent Claim 25 words

The memory device of claim 4, wherein a surface area of the memory cell is 4F 2 , where F is a minimum feature size.

Claim 9

Dependent Claim 20 words

The memory device of claim 4, wherein the second plate of the trench capacitor is maintained at approximately ground potential.

Claim 10

Dependent Claim 23 words

The memory device of claim 4, wherein the second plate of the trench capacitor comprises poly-silicon that is maintained at a constant potential.

Claim 11

Dependent Claim 24 words

The memory device of claim 4, wherein the pillar has a sub-micron width so as to allow substantially full depletion of the body region.

Claim 12

Dependent Claim 12 words

The memory device of claim 5, wherein the word lines are sub-lithographic.

Claim 13

Dependent Claim 158 words

A memory array comprising: a number of memory cells forming an array with a number of rows and columns, each memory cell including an access transistor having body and first and second source/drain regions formed vertically, outwardly from a substrate and a gate disposed adjacent to only one side of the body, the second source/drain region including an upper semiconductor surface; a trench capacitor, wherein the trench capacitor includes a first plate that is formed integral with the second source/drain region of the access transistor and a second plate of the trench capacitor surrounds the second source/drain of the access transistor; a number of first isolation trenches separating adjacent rows of memory cells; first and second word lines disposed in each of the first isolation trenches and coupled to alternating gates on opposite sides of the trench; and a number of second isolation trenches, each substantially orthogonal to the first isolation trenches and interposed between adjacent memory cells.

Claim 14

Dependent Claim 158 words

A memory array comprising: a number of memory cells forming an array with a number of rows and columns, each memory cell including an access transistor having body and first and second source/drain regions formed vertically, outwardly from a substrate and a gate disposed adjacent to only one side of the body, the second source/drain region including an upper semiconductor surface; a trench capacitor, wherein the trench capacitor includes a first plate that is formed integral with the second source/drain region of the access transistor and a second plate of the trench capacitor surrounds the second source/drain of the access transistor; a number of first isolation trenches separating adjacent rows of memory cells; first and second word lines disposed in each of the first isolation trenches and coupled to alternating gates on opposite sides of the trench; and a number of second isolation trenches, each substantially orthogonal to the first isolation trenches and interposed between adjacent memory cells.

Claim 15

Dependent Claim 23 words

The memory array of claim 11, wherein the gates of the access transistors are each formed integral with one of the word lines.

Claim 16

Dependent Claim 18 words

The memory array of claim 11, wherein the pillars extend outwardly from a semiconductor portion of the substrate.

Claim 17

Dependent Claim 25 words

The memory array of claim 11, wherein a surface area of the memory cell is 4F 2 , where F is a minimum feature size.

Claim 18

Dependent Claim 23 words

The memory array of claim 11, wherein the second plate of the trench capacitor comprises poly-silicon that is maintained at a constant potential.

Claim 19

Dependent Claim 22 words

The memory array of claim 11, wherein the word lines have a width that is less than the minimum feature size, F.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2003-05-23	2003-11-22	2004-05-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2007-05-23	2007-11-22	2008-05-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2011-05-23	2011-11-22	2012-05-23	$7700.00	Window Closed / Lapsed

Circuit and method for a folded bit line memory cell with vertical transistor and trench capacitor

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