Switching element having overlapped wiring connections and method for fabricating semiconductor switching device

Patent metadata

Field	Value
Publication number	US-10340451-B2
Application number	US-201414655920-A
Country	US
Kind code	B2
Filing date	Jan 15, 2014
Priority date	Jan 18, 2013
Publication date	Jul 2, 2019
Grant date	Jul 2, 2019

Abstract

In switching elements each using a two-terminal-type variable resistance element, improper writing or any improper operation is often caused and the reliability of the switching elements cannot be improved easily. A switching element according to the present invention is equipped with a first variable resistance element equipped with a first input/output terminal and a first connection terminal, a second variable resistance element equipped with a second input/output terminal and a second connection terminal, and a rectifying element equipped with a control terminal and a third connection terminal, wherein the first connection terminal, the second connection terminal and the third connection terminal are connected to one another.

First claim

The invention claimed is:

1. A switching element comprising:
a first variable resistance element comprising a first input/output terminal and a first connection terminal;
a second variable resistance element comprising a second input/output terminal and a second connection terminal;
a rectifying element comprising a control terminal and a third connection terminal;
a first wiring connected to the first input/output terminal of the first variable resistance element;
a second wiring connected to the second input/output terminal of the second variable resistance element; and
a third wiring connected to the control terminal of the rectifying element, wherein
the first connection terminal, the second connection terminal and the third connection terminal are interconnected,
one of the first wiring and the second wiring overpasses another of the first wiring and the second wiring,
one of the first wiring and the second wiring is a horizontal line commonly connecting a plurality of first input/output terminals of first variable resistance elements, comprising the first variable resistance element, arranged in a horizontal direction,
the another of the first wiring and the second wiring is a vertical line commonly connecting a plurality of second input/output terminals of second variable resistance elements, comprising the second variable resistance element, arranged in a vertical direction,
the third wiring is a diagonal line commonly connecting a plurality of control terminals of rectifying elements, comprising the rectifying element, arranged in a diagonal direction, and has a folded structure comprising another diagonal line commonly connecting at least one of other control terminals of at least one of other rectifying elements arranged in the diagonal direction located differently from the plurality of control terminals of the rectifying elements, and
the third wiring is configured to be connected to a programming line.

2. The switching element according to claim 1 , wherein the first variable resistance element, the second variable resistance element and the rectifying element comprise a same operating polarity.

3. The switching element according to claim 1 ,
wherein the first variable resistance element is configured to transition from a non-conducting state to a conducting state when electric potential at the first input/output terminal is higher than electric potential at the first connection terminal, and transition from the conducting state to the non-conducting state when the electric potential at the first input/output terminal is lower than the electric potential at the first connection terminal; and
the second variable resistance element is configured to transition from a non-conducting state to a conducing state when electric potential at the second input/output terminal is higher than electric potential at the second connection terminal, and transition from the conducting state to the non-conducting state when the electric potential at the second input/output terminal is lower than the electric potential at the second connection terminal.

4. The switching element according to claim 1 ,
wherein each of the first variable resistance element and the second variable resistance element is a nonvolatile variable resistance element comprising a first electrode, a second electrode and a variable resistance film disposed between the electrodes, the first electrode being an active electrode supplying metallic ions, the variable resistance film being a layer capable of conducting metallic ions, the second electrode being an inactive electrode; and
the rectifying element is a volatile variable resistance element.

5. The switching element according to claim 4 ,
wherein the switching element is formed in a multilayer wiring layer in a semiconductor device,
the first electrode serves as both of a lower electrode and a copper wiring, an insulating barrier film is formed on an upper layer surface of the copper wiring, the insulating barrier film comprises an opening, the variable resistance film is in contact with the lower electrode and the copper wiring in the opening, and the second electrode, the rectifying element and a third electrode are stacked in this order from the bottom on an upper surface of the variable resistance film.

6. The switching element according to claim 5 ,
wherein the variable resistance film is in contact with at least two of the lower electrode and the copper wiring in the opening, and the second electrode, the rectifying element and the third electrode are integrated together between the first and the second variable resistance elements.

7. The switching element according to claim 1 , wherein the rectifying element is made of any one of materials comprising SiN x , TaO x , NbO x , HfO x , TiO x , ZrO x , and WO x or a stacked layer of one or more of the materials.

8. The switching element according to claim 5 , wherein the first electrode is composed mainly of Cu, the second electrode is composed mainly of Ru, and the insulating barrier film is made of SiC, SiCN, or SiN.

9. A semiconductor device comprising:
a plurality of switching elements arranged in an array, in which each switching element comprise the switching element according to claim 1 ,
a plurality of horizontal lines, comprising the horizontal line, connected to at least one of the first input/output terminal of the first variable resistance element in the switching elements,
a plurality of vertical lines, comprising the vertical line, connected to at least one of the second input/output terminal of the second variable resistance element in the switching elements, and
a plurality of diagonal lines, comprising the diagonal line, connected to at least one of the control terminal of the rectifying element in the switching elements.

10. The switching element according to claim 1 , wherein
one of the horizontal line, the vertical line and the diagonal line overpasses others of the horizontal line, the vertical line and the diagonal line.

11. The switching element according to claim 1 , wherein at least another one of the control terminals interposes between the control terminal and the at least one of other control terminals.

12. A semiconductor device comprising a bipolar variable resistance element in a multilevel copper wiring layer on a semiconductor substrate, the semiconductor device comprising:
a plurality of first electrodes and copper wirings formed in the multilevel copper wiring layer;
an insulating barrier film formed on the plurality of first electrodes and copper wirings;
an opening formed in the insulating barrier film, the opening being connected with the first electrodes and copper wirings and having a tapered wall surface becoming wider with distance from the copper wirings;
a variable resistance film formed on a planar surface having the opening;
a second electrode formed on the variable resistance film;
a rectifying element formed on the second electrode;
a third electrode formed on the rectifying element;
a first wiring connected to one of the plurality of first electrodes and the copper wirings;
a second wiring connected to another one of the plurality of first electrodes and the copper wirings; and
a third wiring connected to the third electrode formed on the rectifying element, wherein
one of the first wiring and the second wiring overpasses another of the first wiring and the second wiring,
one of the first wiring and the second wiring is a horizontal line commonly connecting a plurality of first input/output terminals of first variable resistance elements, comprising a first variable resistance element, arranged in a horizontal di

Assignees

• Nec Corp

Inventors

• Tada Munehiro
• Sakamoto Toshitsugu
• Banno Naoki
• Okamoto Koichiro

Classifications

• H01L45/1233

  Electricity · mapped topic

• H01L27/2418

  Electricity · mapped topic

• G11C13/0002 Primary

  using resistive RAM [RRAM] elements · CPC title

• H01L45/06

  Electricity · mapped topic

• H01L45/085

  Electricity · mapped topic