# US 2018/0022103 A1 · Printheads with eprom cells having etched multi-metal floating gates

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- Number: US 2018/0022103 A1
- Document ID: US20180022103A1
- Status: Published application
- Kind: A1
- Application number: 15/546,085
- Filed: 2015-04-10
- Published: 2018-01-25
- Earliest claimed: 2015-04-10
- Assignees: Hewlett-Packard Development Company, L.P.
- Applicants: Hewlett-Packard Development Company, L.P.
- Inventors: Ning GE; Zhiyong LI; Ser Chia KOH; Chaw Sing HO
- Web page: https://patentgrep.com/patent/US20180022103A1

## CPC

- B41J 2/17546: {electronically}
- B41J 2/14016: {Structure of bubble jet print heads}
- B41J 2/175: Ink supply systems {; Circuit parts therefor}
- B41J 2/1753: {Details of contacts on the cartridge, e.g. protection of contacts}
- H10B 41/30: characterised by the memory core region
- B41J 2202/17: Readable information on the head
- H10D 64/661: {the conductor comprising a layer of silicon contacting the insulator, e.g. polysilicon having vertical doping variation (having lateral variation in the gate structure H10D64/671)}
- H10D 64/691: {comprising metallic compounds, e.g. metal oxides or metal silicates (insulators comprising nitrogen H10D64/693)}
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- H10B: ELECTRONIC MEMORY DEVICES
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

In one example in accordance with the present disclosure a printhead with a number of EPROM cells is described. The printhead deposits fluid onto a print medium. The printhead also includes a number of EPROM cells. Each EPROM cell includes a substrate having a source and a drain disposed therein, a floating gate separated from the substrate by a first dielectric layer. The floating gate includes a multi-metal layer that is a metal etched layer. Each EPROM cell also includes a control gate separated from the multi-metal layer of the floating gate by a second dielectric layer.

## Claims

### Claim 1

A printhead with a number of erasable programmable read only memory (EPROM) cells, the printhead comprising:
a number of nozzles to deposit an amount of fluid onto a print medium, each nozzle comprising:
a firing chamber to hold the amount of fluid;
an opening to dispense the amount of fluid onto the print medium; and
an ejector to eject the amount of fluid through the opening; and
a number of EPROM cells, each EPROM cell comprising:
a substrate having a source and a drain disposed therein;
a floating gate separated from the substrate by a first dielectric layer, in which:
the floating gate comprises a multi-metal layer; and
the multi-metal layer is a metal etched layer; and
a control gate separated from the multi-metal layer of the floating gate by a second dielectric layer,

### Claim 2 (depends on 1)

The printhead of claim 1, in which the fluid is inkjet ink.

### Claim 3 (depends on 1)

The printhead of claim 1, in which the floating gate further comprises a polysilicon layer electrically coupled to the multi-metal layer.

### Claim 4 (depends on 1)

The printhead of claim 1, in which the multi-metal layer comprises a first sub-layer disposed underneath a second sub-layer, in which a portion of the second sub-layer is etched to expose a portion of the first sub-layer.

### Claim 5 (depends on 4)

The printhead of claim 4, in which the second dielectric layer is formed by oxidation of the exposed portion of the first sub-layer.

### Claim 6 (depends on 4)

The printhead of claim 4, in which:
the first sub-layer is a tantalum aluminum alloy; and
the second sub-layer is an aluminum alloy.

### Claim 7 (depends on 1)

The printhead of claim 1, in which the second dielectric layer is between 2 and 100 nanometers thick.

### Claim 8 (depends on 1)

The printhead of claim 1, in which the number of EPROM cells are disposed in rows and columns in an EPROM array.

### Claim 9

A printer cartridge having a number of programmable read only memory (EPROM) cells, the cartridge comprising:
a fluid supply; and
a printhead to deposit fluid from the fluid supply onto a print medium, the printhead comprising:
a number of EPROM cells, each EPROM cell comprising:
a substrate having a source and a drain disposed therein;
a floating gate separated from the substrate by a first dielectric layer, the floating gate comprising:
a polysilicon layer separated from the substrate by a first dielectric layer; and
a multi-metal layer separated from the polysilicon layer by a third dielectric layer; in which:
the multi-metal layer contacts the polysilicon layer through a gap in the third dielectric layer; and
the multi-metal layer is a metal etched structure; and
a control gate separated from the substrate by a second dielectric layer, in which the second dielectric layer is formed from oxidation of one sub-layer of the multi-metal layer.

### Claim 10 (depends on 9)

The cartridge of claim 9, in which:
the fluid is inkjet ink;
the printer cartridge is an inkjet printer cartridge; and
the printhead is an inkjet printhead.

### Claim 11 (depends on 9)

The cartridge of claim 9, in which the second dielectric: layer comprises tantalum aluminum oxide.

### Claim 12 (depends on 9)

The cartridge of claim 9, in which:
the multi-metal layer comprises a first sub-layer disposed underneath a second sub-layer; and
the multi-metal layer is etched such that a portion of the second sub-layer is etched while retaining the first sub-layer.

### Claim 13 (depends on 9)

The cartridge of claim 9, in which:
the printhead comprises an ejector to eject the fluid; and
the ejector is formed of the same material as the multi-metal layer of the EPROM cell.

### Claim 14 (depends on 13)

The cartridge of claim 13, in which the ejector is formed in a same layer as the multi-metal layer of the EPROM cell.

### Claim 15 (depends on 9)

The cartridge of claim 9, in which the gap in the third dielectric layer s filled with the first sub-layer of the multi-metal layer.