Virtual ground sensing circuitry and related devices, systems, and methods for crosspoint ferroelectric memory

• US 10,360,965 B2
• Filed: 08/10/2017
• Issued: 07/23/2019
• Est. Priority Date: 05/20/2015
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Marotta, Giulio Giuseppe, Tiburzi, Marco Domenico
• Primary Examiner(s): Leboeuf, Jerome
• Application Number:
  US15/674,050
• Publication Number:
  US 20170365320A1
• Time in Patent Office: 712 Days
• CPC Class Codes: G11C 11/221 using ferroelectric capacitors
• CPC Class Codes: G11C 11/2253 Address circuits or decoders
• CPC Class Codes: G11C 11/2273 Reading or sensing circuits or methods
• CPC Class Codes: G11C 11/5657 using ferroelectric storage elements
• CPC Class Codes: G11C 2213/77 Array wherein the memory element being directly connected to the bit lines and word lines without any access device being used
• CPC Class Codes: G11C 7/062 Differential amplifiers of non-latching type, e.g. comparators, long-tailed pairs
• CPC Class Codes: G11C 7/067 Single-ended amplifiers

Abstract

A virtual ground sensing circuit includes a sense circuit configured to compare a reference voltage potential to a sense node voltage potential, and virtual ground circuitry operably coupled to the sense circuit. The virtual ground circuitry is configured to provide a virtual ground at a first bias voltage potential to a conductive line operably coupled to a selected ferroelectric memory cell, and discharge the conductive line to the sense node responsive to the selected ferroelectric memory cell changing from a first polarization state to a second polarization state. A method includes applying a second bias voltage potential to another conductive line operably coupled to the selected ferroelectric memory cell, and comparing a sense node voltage potential to a reference voltage potential. Electrical systems and computing devices include virtual ground sensing circuits.

Claims

1. A control circuit comprising:

a virtual ground sensing circuit configured to;

provide a virtual ground to a conductive line;

selectively operably couple the conductive line to a sense node of a sense circuit, the sense node having a sense node capacitance less than a capacitance of the conductive line; and

compare a sense node voltage to a reference voltage;

wherein the virtual ground sensing circuit is further configured to sense a change in voltage of the sense node; and

wherein the change in voltage at the sense node is defined by a ratio of the change in voltage at the sense node to a change in voltage at the conductive line, wherein the change in voltage at the sense node to the change in voltage at the conductive line are inversely proportional to the ratio of the sense node capacitance and the capacitance of the conductive line.

2. The control circuit of claim 1, wherein the sense node capacitance is less than about 1 picoFarad.

3. The control circuit of claim 1, further comprising a power supply capacitively coupled to the sense node.

4. The control circuit of claim 1, wherein the change in voltage at the conductive line is between 200 microvolts (μ

V) and 500 microvolts (μ

V).

5. The control circuit of claim 1 wherein at least one of the sense node capacitance and the capacitance of the conductive line is defined by a capacitor.