JPH0713661A - Semiconductor integrated circuit and its using method - Google Patents

Abstract

PURPOSE:To operate a circuits and to hold data in a relatively short time without a battery or a power source connected from an outside at the time of using the circuit. CONSTITUTION:A memory circuit part M and a power source circuit part A are provided on the same substrate. In the power source circuit part A, a capacitor C constituted of a high dielectric is serially connected with a resistance R. First, a voltage is impressed from an outside power source to a power source terminal V, and charged in the capacitor C. Next, when the outside power source is disconnected, a charged charge Q is discharged through the resistance R, and current is supplied to the memory circuit M. The insulating film of the capacitor C is SrTiO3 whose area is 1cm<2>, thickness is 10A, and dielectric film constant is 200. For example, the current consumption of a memory circuit with 4000 gates is almost 0.3mumA, and when the voltage impressed from the outside power source is 10V, 6000 second = 100 minute memory holding can be attained. Thus, information can be transferred while secrecy can be held in an IC memory or an IC card, and information can be prevented from leaking by automatically deleting data after the lapse of a holding time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor integrated circuit having an arithmetic circuit, a memory circuit or a sensor element and a method of using the semiconductor integrated circuit.

[0002]

2. Description of the Related Art Semiconductor integrated circuits are widely used in computers, televisions, various control systems and the like. In particular, recently, it has been incorporated in a portable device such as an IC card, and has been further miniaturized and made to have a higher voltage. By the way, generally, many semiconductor integrated circuits are used by connecting a power source of a constant voltage from outside the chip. In the usual case, the semiconductor integrated circuit is mounted on a chip holder, mounted in a socket, and operated by connecting a power source from the outside. If there is no power supply in a normal logic circuit or RAM (random access memory) memory,
Do not work. As a memory that can hold a memory without a power source, an EEPROM (a read-only memory that can be electrically erased and written), a flash memory, and the like have been developed. Further, the battery may be mounted on the same chip holder together with the semiconductor integrated circuit.

[0003]

The portable device is expected to be smaller and lighter, and the battery is a major obstacle for the portable device. Due to the chemical nature of batteries, batteries are dangerous and need to be treated as hazardous waste.

Japanese Unexamined Patent Publication No. 61-15537 discloses that a large-capacity capacitor is connected to a power supply unit of a timepiece IC and used as a backup in case of power failure or voltage drop. Japanese Utility Model Laid-Open No. 63-19784 discloses an IC socket provided with a backup capacitor. In addition, JP-A-2-133728
The publication describes that a backup battery and a backup capacitor are placed on the same printed circuit board as the volatile memory IC, and backup is performed by this capacitor when the battery is replaced. Further, Japanese Patent Application Laid-Open No. 2-158892 discloses that a large-capacity capacitor is mounted as a power source for an IC card terminal and a solar cell is also built in to charge the power source. Further, Japanese Patent Application Laid-Open No. 62-7343 discloses a backup power supply circuit for an IC memory in which a capacitor and a battery are connected in parallel between a power supply line and the IC memory circuit. However, both of these are based on the assumption that an external power source or a battery is used by connecting to a memory or a timepiece IC circuit, and thus have the same problems as described above.

Further, in a memory element such as an EEPROM or a flash memory which does not require a battery, a relatively high voltage is required for writing.

An object of the present invention is to provide a semiconductor integrated circuit which can operate a logic circuit or a sensor element for a relatively short time and retain data without using a battery or a power supply connected from the outside, and a method of using the semiconductor integrated circuit. Especially.

[0007]

The present invention is a semiconductor integrated circuit having an arithmetic circuit, a memory circuit or a sensor circuit on the same substrate, and an element having a storage function made of a high dielectric material.

Further, this is connected to a battery or an external power source to store electricity in an element having an electricity storage function, and then the battery or the external power source is removed to use a semiconductor integrated circuit.

[0009]

By forming a capacitor made of a high dielectric material with a logic circuit or the like on the same substrate, it is possible to accumulate charges. It is possible to operate without connecting the power supply line from the outside, and there is no complexity of preparation and connection of the power supply, and it is lightweight. Also, since it does not have a battery, it can be used in a device that is not used repeatedly, and there is no problem of battery disposal at that time.

[0010]

1 is a diagram showing the configuration of a power supply circuit of an IC memory according to an embodiment of the present invention. Code V is "In the beginning"
A positive power supply terminal to which a DC voltage is applied, and a diode D
The cathode of No. 1 is connected to the power supply line L1. The power supply line L2 is grounded, and the memory circuit M of the IC memory is installed between the power supply lines L1 and L2. Reference numeral A is a power supply circuit section made of a high dielectric material, and power supply lines L1 and L
A resistor R and a capacitor C made of a high dielectric material are arranged in series between the two.

In this structure, when a DC voltage is supplied to the power supply terminal V, power is supplied to the memory circuit section M via the diode D1 and electric charge Q is stored in the capacitor C through the resistor R. Next, when the power source is cut off from the power source terminal V, the charge Q accumulated in the capacitor C is transferred to the resistor R.
Be discharged through. Then, charges are supplied to the memory circuit section.

FIG. 2 shows the relationship between the dielectric constant and the capacitance of a capacitor having an area of 1 cm ² and a thickness of 10A. Barium titanate (BaTiO ₃ ) and strontium titanate (S
The relative permittivity of rTiO ₃ is about 100 and 20 respectively.
0, in which case the capacity is 8.8 × 10 ^{- 4} and 1.78 × 10 ^- a ⁴ Farad. By the way, generally, the current consumption of an IC memory or the like is about 0.3 to 1 .mu.A in the current 4,000 gate memory circuit. Now dielectric constant as 200, 1.78 × 10 ^{- 4} was charged at 10V capacitor capacity of Farad, time use of IC memory that consumes a current of 0.3 .mu.A, t, is 1.78 × 10 ^{- 4 × 10 = 0.3 × 10 - 6} × t from t = 6000 (sec), and the it is possible to approximately 100 minutes memory retention. Moreover, in this embodiment, the capacity is charged and the battery can be reused by reconnecting the DC power supply to the power supply terminal.

An IC memory or IC card having such a storage function can store data without a battery for a relatively short time. For example, it becomes possible to quickly transfer information while maintaining confidentiality in an IC memory or IC card. Moreover, in this case, since the data is automatically erased when the holding time is exceeded, it is possible to further prevent information leakage.

In the device of this embodiment, the memory circuit and the storage element can be formed on the same substrate. Therefore, although the manufacturing process becomes long, the process of mounting on the chip holder becomes shorter and the reliability is improved as compared with the case of individually forming.

Further, since this apparatus does not support the power supply by the battery, it is not necessary to consider the problem of treating hazardous waste such as the battery.

Although the present invention has been described by using the memory card in the embodiments, it is obvious that the present invention may be applied to an apparatus having a sensor element and an arithmetic circuit using a silicon substrate.

[0017]

As described above, according to the present invention, there is no need to mount or carry a power source, and it is not necessary to consider the problem of battery disposal. Particularly in the case of a sensor element used outdoors, it may be possible to reduce the weight and make the device disposable.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a dielectric constant and a capacitance of a capacitor having an area of 1 cm ² and a thickness of 10A.

[Explanation of symbols]

 V power supply terminal C capacitor D1 diode R resistance M memory A power supply circuit section L1, L2 power supply line

Claims (2)

[Claims] 1. A semiconductor integrated circuit having an arithmetic circuit, a memory circuit, or a sensor circuit on the same substrate and an element having a storage function made of a high dielectric material. 2. The semiconductor integrated circuit according to claim 1, wherein a battery or an external power supply is connected to store the power in an element having a power storage function, and then the battery or the external power supply is removed to use the circuit. How to use.