KR20110057839A - Rfid device - Google Patents

Abstract

PURPOSE: An RFID apparatus is provided to reduce the size of layout by dividing an RFID circuit into a capacitor area and a ReRAM area within the same wafer. CONSTITUTION: A radio signal processor processes a wireless signal which is applied from an antenna. A memory(300) performs data read/write according to the output of the radio signal processor. The radio signal processor includes a ferroelectric capacitor. The memory includes a ReRAM(Resistive RAM) having a memristor characteristics. The memory includes a non-volatile register(310) and a non-volatile memory(320).

Description

RFID device {RFID device}

The present invention relates to an RFID device, and is a technology for automatically identifying an object by transmitting and receiving a wireless signal through an external reader and an antenna.

RFID (Radio Frequency IDentification Tag Chip) is a contactless automatic identification method that communicates with an RFID reader by attaching an RFID tag to an object to be identified and automatically transmitting and receiving it by using a wireless signal. To provide technology. As RFID is used, it is possible to compensate for the disadvantages of the conventional automatic identification technology, barcode and optical character recognition technology.

Recently, RFID tags have been used in various cases, such as logistics management systems, user authentication systems, electronic money systems, transportation systems.

For example, in the logistics management system, cargo classification or inventory management is performed using an integrated circuit (IC) tag in which data is recorded instead of a delivery slip or a tag. In the user authentication system, admission management and the like are performed using an IC card that records personal information and the like.

Meanwhile, a nonvolatile ferroelectric memory may be used as a memory used for an RFID tag.

In general, nonvolatile ferroelectric memory, or ferroelectric random access memory (FeRAM), has a data processing speed of about dynamic random access memory (DRAM) and is attracting attention as a next-generation memory device because of its characteristic that data is preserved even when the power is turned off. have.

The FeRAM is a device having a structure almost similar to that of a DRAM, and uses a ferroelectric capacitor as a memory device. Ferroelectrics have a high residual polarization characteristic, and as a result, the data is not erased even when the electric field is removed.

1 is an overall configuration diagram of a general RFID device.

The RFID device according to the related art includes an antenna unit 1, an analog unit 10, a digital unit 20, and a memory unit 30.

Here, the antenna unit 1 serves to receive a radio signal transmitted from an external RFID reader. The wireless signal received through the antenna unit 1 is input to the analog unit 10 through the antenna pads 11 and 12.

The analog unit 10 amplifies the input wireless signal to generate a power supply voltage VDD which is a driving voltage of the RFID tag. The operation command signal is detected from the input wireless signal, and the command signal CMD is output to the digital unit 20. In addition, the analog unit 10 senses the output voltage VDD and outputs a power-on reset signal POR and a clock CLK to the digital unit 20 for controlling the reset operation.

The digital unit 20 receives the power supply voltage VDD, the power-on reset signal POR, the clock CLK, and the command signal CMD from the analog unit 10, and outputs a response signal RP to the analog unit 10. The digital unit 20 also outputs the address ADD, input / output data I / O, control signal CTR, and clock CLK to the memory unit 30.

In addition, the memory unit 30 reads / writes data using a memory element and stores the data.

Here, the RFID device uses a frequency of several bands, the characteristics of which vary depending on the frequency band. In general, the lower the frequency band, the slower the recognition speed, the RFID device operates in a short distance, and is less affected by the environment. On the contrary, the higher the frequency band, the faster the recognition speed and the longer the distance is affected by the environment.

The present invention has the following object.

First, the layout size can be reduced by dividing the RFID circuit into a hybrid region in the same wafer so that a capacitor region having a linear characteristic and a resistance change memory (ReRAM) region having a MEMRISTOR characteristic can be distinguished from each other. The purpose is to make it.

Secondly, the process of forming the electrode in the capacitor region and the memory region is performed in the same way, and the process cost and time can be reduced by using a separate material in the subsequent process so that the linear characteristics and the memristor characteristics can be distinguished. The purpose is to make it possible.

RFID apparatus of the present invention for achieving the above object, the wireless signal processing means for processing a radio signal applied from the antenna; And a memory unit in which data read / write operation is performed according to the output of the wireless signal processing unit, wherein the wireless signal processing unit includes a ferroelectric capacitor, and the memory unit includes a resistance change memory device.

The present invention has the following effects.

First, in the same wafer, the RFID circuit is divided into a hybrid region so that the capacitor region having the linear characteristic and the resistance change memory (ReRAM) region having the MEMRISTOR characteristic can be distinguished to reduce the layout size. To help.

Secondly, the process of forming the electrode in the capacitor region and the memory region is performed in the same way, and the process cost and time can be reduced by using a separate material in the subsequent process so that the linear characteristics and the memristor characteristics can be distinguished. Provides the effect of reducing it.

In addition, the preferred embodiment of the present invention is for the purpose of illustration, those skilled in the art will be able to various modifications, changes, replacements and additions through the spirit and scope of the appended claims, such configuration changes, etc. It should be seen as belonging to a range.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of a radio frequency identification (RFID) device according to the present invention.

The present invention includes an antenna ANT, an analog unit 100, a digital unit 200, and a memory unit 300. Here, the analog unit 100 may include a voltage multiplier 110, a modulator 120, a demodulator 130, a power on reset unit 140, and a clock generator. (Clock Generator; 150).

The antenna ANT receives a radio signal (RF) transmitted from an RFID reader. The radio signal received by the RFID device is input to the RFID chip through the antenna pads ANT (+) and ANT (-).

The voltage amplifier 110 rectifies and boosts the radio signal applied from the antenna ANT to generate a power supply voltage VDD which is a driving voltage of the RFID device.

The modulator 120 modulates the response signal RP input from the digital unit 200 and transmits the modulated response signal RP to the antenna ANT. The demodulator 130 demodulates the radio signal input from the antenna ANT according to the output voltage of the voltage amplifier 110 and outputs the command signal CMD to the digital unit 200.

In addition, the power-on reset unit 140 detects the power supply voltage generated by the voltage amplifier 110 and outputs a power-on reset signal POR for controlling the reset operation to the digital unit 200. Here, the power-on reset signal POR rises together with the power supply voltage while the power supply voltage transitions from the low level to the high level, and then transitions from the high level to the low level as soon as the power supply voltage is supplied to the power supply voltage level VDD. Means a signal to reset the circuit.

The clock generator 150 supplies the clock CLK for controlling the operation of the digital unit 200 according to the power voltage generated by the voltage amplifier 110 to the digital unit 200.

In addition, the digital unit 200 receives a power supply voltage VDD, a power-on reset signal POR, a clock CLK, and a command signal CMD, interprets the command signal CMD, and generates control signals and processing signals. The digital unit 200 outputs a response signal RP corresponding to the control signal and the processing signals to the modulator 120. The digital unit 200 also outputs the address ADD, data I / O, control signal CTR, and clock CLK to the memory unit 300.

In addition, the memory unit 300 includes a plurality of memory cells, each of which serves to write data to the storage device and to read data stored in the storage device.

The memory unit 300 includes a resistive random access memory device (ReRAM). The resistance change memory device (ReRAM) is a nonvolatile memory device that changes an electrical resistance of a material by applying an external voltage to a thin film and uses the resistance difference on or off.

FIG. 3 is a diagram illustrating a region of use of a ferroelectric capacitor and a region of use of a resistance change memory device (ReRAM) in the RFID device of FIG. 2.

The present invention divides an RFID circuit into a hybrid region. That is, it is divided into a region using a ferroelectric capacitor having a linear characteristic and a region using a resistance change memory device (ReRAM) having a MEMRISTOR characteristic. The hybrid region is divided into a capacitor region 250 including an analog unit 100, a digital unit 200, and a memory unit 300 including a resistance change memory device (ReRAM).

The memory unit 300 is divided into a nonvolatile register 310 and a nonvolatile memory 320. The nonvolatile register 310 and the nonvolatile memory 320 non-volatile store data applied through the analog unit 100 and the digital unit 200.

The fourth electronic circuit component, followed by resistors, capacitors, and inductors, is called MEMRISTOR, short for memory resistor or resistive memory. The main difference between these memristors and other circuit elements is that they can store non-volatile data about previous information. That is, the memristor (MEMRISTOR), the resistance value changes with the flow of current, it has the characteristic that the changed resistance value is maintained as it is.

4 illustrates a configuration of the capacitor region 250 and the memory unit 300.

Here, FIG. 4A illustrates a capacitor configuration of the capacitor region 250 including the analog unit 100 and the digital unit 200. The capacitor region 250 including the analog unit 100 and the digital unit 200 is defined as a 'wireless signal processing unit' for processing a radio signal RF applied from the antenna ANT.

4B illustrates a configuration of the memory unit 300 including the resistance change memory device (ReRAM). The capacitor configurations of the capacitor region 250 and the memory unit 300 are different from each other.

That is, the ferroelectric capacitor of the capacitor region 250 as shown in FIG. 4A has a structure in which the first electrode 251, the ferroelectric film 252, and the second electrode 253 are sequentially stacked.

In the nonvolatile circuit region of the memory unit 300 as illustrated in FIG. 4B, the first electrode 330, the transition metal oxide film 331, and the second electrode 332 are sequentially stacked. Here, the transition metal oxide film 331 may be made of a material such as TiO 2.

FIG. 5 is a diagram for describing ferroelectric capacitor characteristics in the capacitor region 250 applied to the analog unit 100 and the digital unit 200.

A capacitor having a structure as shown in FIG. 4A has a structure in which a first electrode 251, a ferroelectric layer 252, and a second electrode 253 are sequentially stacked. In general, the ferroelectric capacitor has a structure substantially similar to that of a DRAM, and has a high residual polarization characteristic of the ferroelectric by using the ferroelectric film 252 as the material of the capacitor. Due to this residual polarization characteristic, ferroelectric capacitors do not erase their data when the electric field is removed.

However, the present invention does not include a hydrogen barrier film or the like which prevents the penetration of hydrogen in the subsequent process of the ferroelectric capacitor.

As a result, the degradation factor of the hysteresis characteristic of the ferroelectric film 252 generated in a process such as an insulating film or metal etching in a subsequent process is affected. Therefore, the hysteresis curve, which is an inherent characteristic of the ferroelectric capacitor, is converted into a linear characteristic.

That is, the ferroelectric capacitor applied to the capacitor region 250 has a characteristic of a linear capacitor. Accordingly, as in (C), as the voltage (Voltage) increases, the charge (Charge) is increased to have a linear characteristic.

FIG. 6 is a diagram for describing a characteristic of a MEMRISTOR in a nonvolatile circuit region including the memory unit 300.

The resistance change memory device ReRAM having the structure as shown in FIG. 4B has a structure in which the first electrode 330, the transition metal oxide film 331, and the second electrode 332 are sequentially stacked.

Accordingly, as in (D), when the voltage (Voltage) increases in the positive direction, the current rises with a constant slope. When the voltage becomes higher than or equal to the threshold voltage, the current is rapidly increased. Thereafter, as the voltage decreases, the current drops to a constant slope. If the voltage decreases in the negative direction, the current decreases with a constant slope. And when the voltage becomes below the threshold voltage, the current will rise rapidly. Thereafter, as the voltage increases again, the current rises with a constant slope.

That is, the resistance change memory device (ReRAM) has memristor characteristics by the transition metal oxide film 331. The resistance change memory device (ReRAM) is repeatedly increased and decreased depending on the voltage.

In the present invention, a ferroelectric capacitor having a linear characteristic is applied to the capacitor region 250 including the analog unit 100 and the digital unit 200.

The characteristic of the linear capacitor is fixed to a constant value of the capacitance (Capacitance) compared to the characteristic of the hysteresis capacitor. In addition, since the linear capacitor has a large capacitance value, it is possible to use a capacitor having a small layout size.

Accordingly, in the capacitor region 250 including the analog unit 100 and the digital unit 200, the layout area due to the capacitor can be reduced, thereby reducing the unit cost of the chip.

In addition, a device having a MEMRISTOR characteristic is applied to a region of the memory unit 300 including the resistance change memory device (ReRAM).

7 to 10 illustrate a process of forming the capacitor region 250 and the memory unit 300.

The present invention divides an RFID circuit into a ferroelectric capacitor region and a resistance change memory (ReRAM) region in the same wafer. Accordingly, as shown in FIG. 7, the first electrode 251 of the ferroelectric capacitor and the first electrode 330 of the resistance change memory device (ReRAM) are formed by the same process. Here, the first electrode 251 and the first electrode 330 are preferably made of platinum material (Pt).

Subsequently, as shown in FIG. 8, a ferroelectric film 252 having a linear characteristic is formed on the first electrode 251. Here, it is preferable that the ferroelectric film 252 uses PZT (Plumbum-Zirconate-Titanate) as a dielectric. Since the PZT has a high dielectric constant, it is possible to reduce the area of the capacitor used for RFID.

Subsequently, as shown in FIG. 9, a transition metal oxide film 331 having memristor characteristics is formed on the first electrode 330. Here, the transition metal oxide film 331 is preferably made of a TiO 2 material.

In this case, the transition metal oxide film 331 is preferably formed to have a predetermined thickness thinner than the ferroelectric film 252. The thinner the thickness of the transition metal oxide film 331, the lower the resistance, and a higher current can flow.

Accordingly, the characteristics of the ferroelectric film are separated from the capacitor region 250 of the analog unit 100 and the digital unit 200 and the region of the memory unit 300 so that the linear characteristics and the memristor characteristics are distinguished. Done.

That is, without forming a hydrogen barrier layer on the capacitor of the capacitor region 250, a transition metal oxide material is additionally formed in the memory unit 300 through a subsequent process. Accordingly, the electrode forming process is performed in the same manner, but in the subsequent process, the ferroelectric characteristics and the memristor characteristics are different from each other in the two circuit regions, thereby reducing the process cost and time.

Next, as shown in FIG. 10, the process of forming the second electrode 253 of the ferroelectric capacitor and the second electrode 332 of the resistance change memory device (ReRAM) are performed in common. Here, the second electrode 253 and the second electrode 332 are preferably made of platinum material (Pt).

1 is a block diagram of a conventional RFID device.

2 is a block diagram of an RFID device according to the present invention.

3 is a view for explaining a capacitor region and a memory region in the RFID device of FIG.

4 is a cross-sectional view of a capacitor region and a memory region in the RFID device of FIG. 2.

5 and 6 are graphs for explaining the characteristics of the capacitor region and the memory region in FIG.

7 through 10 are cross-sectional views illustrating a process of forming a capacitor region and a memory region in FIG. 4.

Claims (10)

Radio signal processing means for processing radio signals applied from an antenna; And And a memory unit for performing read / write operation of data according to the output of the wireless signal processing means. The wireless signal processing means includes a ferroelectric capacitor, and the memory unit comprises a resistance change memory element. The method of claim 1, wherein the radio signal processing means An analog unit for outputting a command signal according to the radio signal and outputting a signal corresponding to a response signal to the outside through the antenna; And And a digital unit outputting an operation control signal to the memory unit according to the command signal, and outputting the response signal to the analog unit. The method of claim 2, wherein the analog unit A voltage amplifier configured to generate a driving voltage according to the wireless signal; A modulator for generating a modulated signal according to the response signal; A demodulator for demodulating the radio signal to generate the command signal; A power on reset unit generating a power on reset signal according to the driving voltage; And And a clock generator for generating a clock according to the driving voltage. The RFID device of claim 1, wherein the ferroelectric capacitor has a linear characteristic. The RFID device according to claim 4, wherein the ferroelectric capacitor includes a first electrode, a ferroelectric film, and a second electrode. The RFID device of claim 1, wherein the memory unit comprises a nonvolatile register and a nonvolatile memory for storing the data nonvolatilely. The RFID device according to claim 1, wherein the resistance change memory device has a memristor characteristic. The RFID device of claim 7, wherein the resistance change memory device comprises a first electrode, a transition metal oxide film, and a second electrode. The RFID device according to claim 1, wherein the ferroelectric capacitor has a linear capacitor characteristic, and the resistance change memory device has a memristor characteristic. 10. The method of claim 9, wherein the ferroelectric capacitor and the resistance change memory device have the same electrode formation, and after forming the ferroelectric film of the ferroelectric capacitor, subsequently forming a transition metal oxide film of the resistance change memory device. An RFID device.

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