# US 5,705,843 A · Integrated circuits and SRAM memory cells

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- Number: US 5,705,843 A
- Document ID: US5705843A
- Status: Granted
- Kind: A
- Application number: 08/679,655
- Filed: 1996-07-12
- Granted: 1998-01-06
- Earliest claimed: 1995-03-23
- Assignees: Micron Technology, Inc.
- Inventors: Martin Ceredig Roberts
- Web page: https://patentgrep.com/patent/US5705843A

## CPC

- H10D 1/47: Resistors having no potential barriers
- H10B 10/00: Static random access memory [SRAM] devices
- H10B 10/15: {comprising a resistor load element}
- H10D 84/209: {of only resistors}
- Y10S 257/904: with passive components,, e.g. polysilicon resistors
- Y10S 438/979: Tunnel diodes
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10B: ELECTRONIC MEMORY DEVICES
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

SRAM and other integrated circuitry. In one aspect the invention includes an integrated circuit comprising: a) a first electrically insulating material layer having an outer surface; b) an electrically insulative pillar ring extending substantially vertically outward of the first layer, the pillar ring having opposing inner and outer substantially vertical side surfaces; c) an elongated resistor, the resistor comprising a layer of semiconductive material which serpentines over the first layer outer surface and the pillar ring vertical surfaces to form a container shape resistor within the pillar ring; d) an electrically conductive first node in electrical connection with the resistor on the inside of the insulative pillar ring; and e) an electrically conductive second node in electrical connection with the resistor on the outside of the insulative pillar ring.

## Claims

### Claim 1

An integrated circuit comprising:
a first electrically insulating material layer having an outer surface;
an electrically insulative pillar extending substantially vertically outward of the first layer, the pillar having opposing substantially vertical side surfaces;
an elongated resistor, the resistor comprising a layer of semiconductive material which serpentines over the first layer outer surface and the pillar vertical surfaces;
an electrically conductive first node in electrical connection with the resistor on one side of the insulative pillar; and
an electrically conductive second node in electrical connection with the resistor on the other side of the insulative pillar.

### Claim 2 (depends on 1)

The integrated circuit of claim 1 wherein the pillar predominately comprises an electrically insulative material which is different from the first material.

### Claim 3 (depends on 1)

The integrated circuit of claim 1 wherein the elongated resistor has different conductivity dopant concentrations at different locations within the semiconductive layer.

### Claim 4 (depends on 1)

The integrated circuit of claim 1 wherein the pillar predominately comprises an electrically insulative material which is different from the first material, and wherein the elongated resistor has different conductivity dopant concentrations at different locations within the semiconductive layer.

### Claim 5

An integrated circuit comprising:
a first electrically insulating material layer having an outer surface;
an electrically insulative pillar ring extending substantially vertically outward of the first layer, the pillar ring having opposing inner and outer substantially vertical side surfaces;
an elongated resistor, the resistor comprising a layer of semiconductive material which serpentines over the first layer outer surface and the pillar ring vertical surfaces to form a container shape resistor within the pillar ring;
an electrically conductive first node in electrical connection with the resistor on the inside of the insulative pillar ring; and
an electrically conductive second node in electrical connection with the resistor on the outside of the insulative pillar ring.

### Claim 6 (depends on 5)

The integrated circuit of claim 5 wherein the pillar ring predominately comprises an electrically insulative material which is different from the first material.

### Claim 7 (depends on 5)

The integrated circuit of claim 5 wherein the container shape includes an outer portion and an inner portion, the inner portion having higher conductivity doping than the outer portion.

### Claim 8 (depends on 5)

The integrated circuit of claim 5 wherein the pillar predominately comprises an electrically insulative material which is different from the first material, and wherein the container shape includes and outer portion and an inner portion, the inner portion having higher conductivity doping than the outer portion.

### Claim 9

An SRAM cell comprising:
a first pull down transistor having a gate, a source and a drain;
a second pull down transistor having a gate, a source and a drain;
the gate of the first pull down transistor being electrically coupled to the drain of the second pull down transistor;
the gate of the second pull down transistor being electrically coupled to the drain of the first pull down transistor;
a Vcc node;
a first resistor electrically coupled with the Vcc node;
a second resistor electrically coupled with the Vcc node;
the drain of the first pull down transistor being electrically coupled through the first resistor to the Vcc node;
the drain of the second pull down transistor being electrically coupled through the second resistor to the Vcc node; and
at least one of the first and second resistors comprising:
a first electrically insulating material layer having an outer surface;
an insulative pillar ring extending substantially vertically outward of the first layer, the pillar ring having opposing inner and outer substantially vertical side surfaces;
an elongated resistor, the resistor comprising a layer of semiconductive material which serpentines over the first layer outer surface and the pillar ring vertical surfaces to form a container shape resistor within the pillar ring;
an electrically conductive first node in electrical connection with the resistor on the inside of the insulative pillar ring; and
an electrically conductive second node in electrical connection with the resistor on the outside of the insulative pillar ring.

### Claim 10 (depends on 9)

The SRAM cell of claim 9 wherein both of the first and second resistors comprise the stated container shape.

### Claim 11 (depends on 9)

The SRAM cell of claim 9 wherein the pillar ring predominately comprises an electrically insulative material which is different from the first material.

### Claim 12 (depends on 9)

The SRAM cell of claim 9 wherein the container shape includes an outer portion and an inner portion, the inner portion having higher conductivity doping than the outer portion.

### Claim 13 (depends on 9)

The SRAM cell of claim 9 wherein the pillar predominately comprises an electrically insulative material which is different from the first material, and wherein the container shape includes an outer portion and an inner portion, the inner portion having higher conductivity doping than the outer portion.

### Claim 14

An integrated circuit comprising:
a first electrically insulating material layer having an outer surface;
an electrically insulative pillar extending outward of the first layer, the pillar having opposing substantially vertical side surfaces;
an elongated resistor, the resistor comprising a layer of semiconductive material which overlays the first layer outer surface and overlays the pillar vertical surfaces;
an electrically conductive first node in electrical connection with the resistor on one side of the insulative pillar; and
an electrically conductive second node in electrical connection with the resistor on the other side of the insulative pillar.

### Claim 15

An integrated circuit comprising:
a first electrically insulating material layer having an outer surface;
an electrically insulative pillar ring extending outward of the first layer, the pillar ring having opposing inner and outer substantially vertical side surfaces;
an elongated resistor, the resistor comprising a layer of semiconductive material which overlays the first layer outer surface and overlays the pillar ring vertical surfaces to form a container shape resistor within the pillar ring;
an electrically conductive first node in electrical connection with the resistor on the inside of the insulative pillar ring; and
an electrically conductive second node in electrical connection with the resistor on the outside of the insulative pillar ring.