JP2001237380A - Variable resistance element and semiconductor device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems that circuits in an FPGA using anti-fuses cannot be rewritten several times but only once because of its operation characteristics, circuits in an FPGA using an SRAM can be rewritten any number of times, but the power consumption increases, the memory cannot be held with power set off and hence it needs to re-store information in a RAM, and a flash memory has a low writing rate of about several milliseconds, a high writing voltage of 8-12 V and a little write-erase repetition of about several hundred thousand times. SOLUTION: In the variable resistive element composed of a resistance body with electrodes at the ends, the resistance body is an oxide containing as a main component any metal selected among a group of following materials.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a variable resistance element, a semiconductor memory device, a semiconductor large-scale integrated circuit and the like used in electronic equipment.

[0002]

2. Description of the Related Art There is an increasing demand for portable information terminals which are excellent in portability and can easily access a network. These information portable terminals are equipped with a processor for information processing. Usually, dedicated LSIs customized for respective purposes are used. In recent years, along with the diversification of information devices, FPGAs and SRAMs that can reconfigure circuits using antifuse
By sequentially switching the IPs built therein, FPGAs and the like that support various information processing have come to be used. EEPROMs and FLASH memories are non-volatile and electrically recordable and erasable, and are therefore currently mounted on various devices, IC cards, and the like. However, there is a problem that the writing speed of these memories is as low as about millisecond, the writing voltage is as high as 8 to 12 V, or the repetition of writing / erasing is as small as several hundred thousand times.

[0003]

In an FPGA using an antifuse, writing of a circuit is performed only once due to its operating characteristics and cannot be rewritten many times. Also, SR
In the FPGA using the AM, the circuit can be rewritten many times, but the power consumption increases and the memory cannot be held when the power is turned off. Therefore, it is necessary to save the information to the RAM. Further, the flash memory has a problem that the writing speed is as slow as about millisecond, the writing voltage is as high as 8 to 12 V, or the number of repetitions of writing / erasing is as small as several hundred thousand times.

[0004]

According to the present invention, there is provided a variable resistance element comprising a resistor having an electrode at an end, wherein the resistor is an oxide mainly composed of a metal selected from the following substance group. A variable resistance element characterized by the above features.
As the metal oxide, any metal oxide selected from a substance group: silver, lead, copper, Pd, and Ir is used. Moreover,
A semiconductor device having a memory using the variable resistance element is configured. Further, a semiconductor device on which a large-scale semiconductor integrated circuit on which the variable resistance element is mounted is mounted.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments.

A p-type (100) S having a resistance of 0.01 Ω · cm
After forming a SiO ₂ film 2 having a thickness of 100 nm on an i-substrate 1 by thermal oxidation, a platinum electrode 3 having a thickness of 200 nm is formed by a sputtering method, and then a 50 nm-thick film is formed by a CVD method.
After forming a SiO _{2 layer} having a thickness of 0 nm, an opening is formed by ion milling, silver oxide 5 is deposited by a vacuum deposition method, flattening is performed by CMP, and an upper electrode 6 is formed by a sputtering method. Was prepared. FIG. 1 shows a schematic cross-sectional view of the variable resistance element manufactured in this example.

A voltage was applied between the lower electrode 3 and the upper electrode 6 of the variable resistance element to measure the current-voltage of the variable resistance element. The result is shown in FIG. As shown in the figure, the history of the current is observed by applying the voltage. In the variable resistance element manufactured in this example, the current value changed nonlinearly by about two digits when a voltage of 5 V or more was applied, and a history was observed. This voltage history showed no change after 10 ¹⁵ repetitions.
The resistance when 6 V was applied changed at a speed of 1 nanosecond or less, and was below the observation limit of the measuring instrument. Similar results were obtained when lead, copper, Pd, and Ir oxides were used as metal oxides in addition to silver oxide.

Subsequently, as shown in FIG. 3, a circuit element in which variable resistance elements were combined with diodes and arranged in a matrix was fabricated on a semiconductor substrate. When the matrix elements are individually accessed by sequentially switching the X and Y switches and the resistance change according to the current value is examined, the same current-voltage characteristics as shown in FIG. Operation as a device has been demonstrated.

Further, although no study was conducted in this embodiment, it can be easily understood that, for example, a configuration combined with a MOSFET as shown in FIG. 4 is effective for realizing a higher-speed operation. . As described above, the memory device using the variable resistance element having the configuration shown in this embodiment has a simple configuration, and it is extremely easy to realize a memory device having a high recording density.

[0010]

As described above, by implementing the present invention, a high-speed operation variable resistance element can be easily provided, and a nonvolatile semiconductor memory device having a high recording density can be easily provided. The economic effects on the industry are expected to be significant.

[Brief description of the drawings]

FIG. 1 is a sectional view of a variable resistance element manufactured in an example according to the present invention.

FIG. 2 is a view showing current-voltage characteristics of a variable resistance element manufactured in an example according to the present invention.

FIG. 3 is a diagram showing an embodiment when variable resistance elements are arranged in a matrix.

FIG. 4 is a diagram showing a configuration example of a memory element combining a MOS transistor and a variable resistance element;

[Explanation of symbols]

1 Si substrate 2 SiO ₂ 3 lower electrode 4 SiO ₂ 5 metal oxide 6 upper electrode

Continuing from the front page (72) Inventor Takashi Nishikawa 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Reference) 5F038 AV17 CA02 DF05 EZ14 EZ20 5F064 AA08 BB02 BB12 CC22 GG10 5F083 FZ10 JA21 JA38

Claims (9)

[Claims] 1. A variable resistor comprising a resistor having an electrode at an end, wherein the resistor is an oxide containing silver as a main component. 2. A variable resistance element comprising a resistor having an electrode at an end, wherein the resistor is an oxide containing lead as a main component. 3. A variable resistor comprising a resistor having an electrode at an end, wherein the resistor is an oxide containing copper as a main component. 4. A variable resistor comprising a resistor having an electrode at an end, wherein the resistor is an oxide containing Pd as a main component. 5. A variable resistor comprising a resistor having an electrode at an end, wherein the resistor is an oxide containing Ir as a main component. 6. The variable resistance element according to claim 1, wherein a resistance value of the variable resistance element changes according to a current value flowing through the variable resistance element.
The variable resistance element according to any one of the above. 7. The variable resistance element according to claim 1, wherein the resistance value of the variable resistance element changes depending on the duration of the current flowing through the variable resistance element. 8. A semiconductor device comprising a memory using the resistance change of the variable resistance element according to claim 1. 9. A semiconductor device equipped with a large-scale semiconductor integrated circuit, wherein the variable resistance element according to claim 1 is used.