# US 2014/0191336 A1 · Cross-hair cell wordline formation

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- Number: US 2014/0191336 A1
- Document ID: US20140191336A1
- Status: Published application
- Kind: A1
- Application number: 14/209,527
- Filed: 2014-03-13
- Published: 2014-07-10
- Earliest claimed: 2010-02-09
- Assignees: Micron Technology, Inc.
- Applicants: Micron Technology, Inc.
- Inventors: Werner Jeungling
- Web page: https://patentgrep.com/patent/US20140191336A1

## CPC

- H10D 84/834: {comprising FinFETs}
- H10B 12/20: {DRAM devices comprising floating-body transistors, e.g. floating-body cells}
- H10D 30/024: {of fin field-effect transistors [FinFET]}
- H10D 30/60: Insulated-gate field-effect transistors [IGFET] (H10D30/40 takes precedence)
- H10D 30/711: {having floating bodies}
- H10D 64/01: Manufacture or treatment
- H10D 84/8311: {the IGFETs characterised by having different channel structures}
- H10B 12/36: {the transistor being a FinFET}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10B: ELECTRONIC MEMORY DEVICES

## Abstract

Methods and devices depicting fabrication of non-planar access devices having fins and narrow trenches, among which is a method that includes wet etching a conductor to form a recessed region and subsequently etching the conductor to form gates on the fins. The wet etching may include formation of recesses which are may be backfilled with a fill material to form spacers on the conductor. Portions of a plug may be removed during the wet etch to form overhanging spacers to provide further protection of the conductor during the dry etch.

## Claims

### Claim 1

An access device, comprising:
a first fin and a second fin separated by trench;
a conductor disposed in the trench; and
a first overhanging spacer formed on a first sidewall of the trench and a second overhanging spacer formed on a second sidewall second of the trench.

### Claim 2 (depends on 1)

The access device of claim 1, wherein each of the overhanging spacers comprises silicon nitride, aluminum oxide, high temperature oxide, or any combination thereof.

### Claim 3 (depends on 1)

The access device of claim 1, wherein each of the overhanging spacers is provided to protect portions of the conductor disposed on the first sidewall and the second sidewall from etching.

### Claim 4 (depends on 1)

The access device of claim 1, wherein the conductor is disposed on each of the first sidewall and the second sidewall, below each of the overhanging spacers.

### Claim 5 (depends on 1)

The access device of claim 1, wherein each of the overhanging spacers is thicker than the conductor in a direction perpendicular from the first sidewall.

### Claim 6 (depends on 1)

The access device of claim 1, wherein the conductor is not present at the bottom of the trench.

### Claim 7

An access device, comprising:
a fin having a first sidewall and a second sidewall;
a first overhanging spacer formed on the first sidewall; and
a second overhanging spacer formed on the second sidewall.

### Claim 8 (depends on 7)

The access device of claim 7, comprising a first metal conductor formed on the first sidewall, below the first overhanging spacer and a second metal conductor formed on the second sidewall, below the second overhanging spacer.

### Claim 9 (depends on 8)

The access device of claim 8, wherein each of the overhanging spacers is thicker than each of the metal conductors in a direction perpendicular each of the sidewalls.

### Claim 10 (depends on 8)

The access device of claim 8, wherein the first overhanging spacer is formed above the first conductor, and wherein a portion of the first overhanging spacer is formed in the same horizontal plane as the first conductor.

### Claim 11 (depends on 7)

The access device of claim 7, wherein each of the overhanging spacers comprises silicon nitride, aluminum oxide, high temperature oxide, or any combination thereof.

### Claim 12 (depends on 7)

The access device of claim 7, wherein the fin comprises a semiconductor.

### Claim 13 (depends on 7)

The access device of claim 7, wherein the fin comprises an upper doped region and a lower doped region.

### Claim 14 (depends on 13)

The access device of claim 13, wherein the each of the first overhanging spacer and the second overhanging spacer is adjacent to the upper doped region.

### Claim 15 (depends on 7)

The access device of claim 7, wherein the fin comprises a semiconductor having an upper doped region and a pad oxide cap formed on top of the upper doped region.

### Claim 16 (depends on 15)

The access device of claim 15, comprising a silicon nitride cap formed on top of the pad oxide cap.

### Claim 17

An access device, comprising:
a fin having a lower doped region and an upper doped region;
a conductor formed on a sidewall of the fin, adjacent to the lower doped region; and
a overhanging spacer formed on the sidewall of the fin, adjacent to the upper doped region and on top of the conductor.

### Claim 18 (depends on 17)

The access device of claim 17, comprising:
a second conductor formed on a second sidewall of the fin, adjacent to the lower doped region; and
a second overhanging spacer formed on the second sidewall of the fin, adjacent to the upper doped region and on top of the second conductor.

### Claim 19 (depends on 17)

The access device of claim 17, wherein the first overhanging spacer comprises silicon nitride, Al2O3, HTO, or a combination thereof.

### Claim 20 (depends on 17)

The access device of claim 17, wherein a source and a drain are formed in the upper doped region of the fin.