This U.S. non-provisional patent application claims priority under 35 U.S.C. §119 of Korean Patent Application Nos. 10-2013-0078913, filed on Jul. 5, 2013, and 10-2013-0156332, filed on Dec. 16, 2013, the entire contents of which are hereby incorporated by reference.
The present invention disclosed herein relates to a transistor system, and more particularly, to driving of a metal-insulator transition (MIT) transistor.
Typically, one of the representative electronic devices is a transistor having three terminals. This transistor operates on the basis of semiconductor characteristics.
Semiconductor power devices are required to have good characteristics of allowing large currents to flow. However, heat may be greatly generated despite of flowing of not large current. When a size of a transistor becomes small to a nano size level, a short channel effect appears and makes it hard to operate as a transistor. Therefore, a device exceeding limitations of this electronic device has been increasingly requested and many researchers concentrate all their efforts on researches on a device exceeding the limitations.
One of principles of overcoming the limitations is an MIT principle. An MIT transistor, which does not use a field effect but use a hole-driven MIT phenomenon, is disclosed in Korean patent application publication No. 2012-0073002 and an article, “Applied Physics Letters 103, 1735-1(2013); http//scitation.aip.org/content/aip/journal/apl/103/17/10.1063/1.4826223”. However, it is necessary to supply a critical current to allow the MIT phenomenon to occur.
Accordingly, a technology for simply supplying the critical current is necessary.
The present invention provides a current supplier supplying a critical current necessary for allowing an MIT phenomenon to occur in an MIT transistor in order to simply and conveniently drive the MIT transistor.
The present invention also provides an MIT transistor system capable of smoothly driving an MIT transistor.
Embodiments of the present invention provide metal-insulator transition (MIT) transistor systems, including: an MIT transistor; and a current supplier supplying a critical current for allowing an MIT phenomenon to occur between a control terminal and an output terminal of the MIT transistor.
In some embodiments, the current supplier may include a transistor receiving a pulse input signal and generating the critical current.
In other embodiments, the transistor may include an NPN bipolar transistor having a base to which the pulse input signal is received, a collector connected to an input terminal of the MIT transistor, and an emitter connected to the control terminal of the MIT transistor.
In still other embodiments, the transistor may include a PNP bipolar transistor having a base to which the pulse input signal is received, an emitter connected to an input terminal of the MIT transistor, and a collector connected to the control terminal of the MIT transistor.
In even other embodiments, the transistor may include a PNP bipolar transistor having a base to which the pulse input signal is received, an emitter connected to the control terminal of the MIT transistor, and a collector that is grounded.
In yet other embodiments, the transistor may include an NPN bipolar transistor having a base to which the pulse input signal is received, a collector connected to the control terminal of the MIT transistor, and an emitter that is grounded.
In further embodiments, the transistor may include an N type field effect transistor having a gate to which the pulse input signal is received, a drain connected to an input terminal of the MIT transistor, and a source connected to the control terminal of the MIT transistor.
In still further embodiments, the transistor may include an N type field effect transistor having a gate to which the pulse input signal is received, a drain connected to the control terminal of the MIT transistor, and a source that is grounded.
In even further embodiments, the transistor may include a P type field effect transistor having a gate to which the pulse input signal is received, a source connected to an input terminal of the MIT transistor, and a drain connected to the control terminal of the MIT transistor.
In yet further embodiments, the transistor may include a P type field effect transistor having a gate to which the pulse input signal is received, a source connected to the control terminal of the MIT transistor, and a drain that is grounded.
In much further embodiments, the current supplier may supply power induced at a secondary coil of a transformer to the control terminal of the MIT transistor.
In still much further embodiments, the MIT transistor may include, as a current device, a forward active mode bipolar transistor operating in a negative differential resistance (NDR) mode as an MIT phenomenon when a critical current is applied.
In even much further embodiments, the MIT transistor may include, as a current device, a reverse active mode bipolar transistor operating in an NDR mode as an MIT phenomenon when a critical current is applied.
In yet much further embodiments, the MIT transistor may operate in an NDR mode.
In still yet much further embodiments, the current supplier and the MIT transistor may be manufactured on a single identical substrate by monolithic method, or the current supplier and the MIT transistor are manufactured in a same package.
In other embodiments of the present invention, MIT transistor systems includes: an MIT transistor having an input terminal, an output terminal, and a control terminal, and allowing MIT to occur therein; and a current supplier connected between the input and control terminals of the MIT transistor, and, when the input and output terminals are connected between a power supply voltage and a ground voltage, receiving an input signal and allowing the MIT phenomenon to occur between the control and output terminals.
In still other embodiments of the present invention, operation methods of an MIT transistor system, include: connecting, to input and output loads, an MIT transistor having an input terminal, an output terminal, and a control terminal, and allowing MIT to occur therein; receiving an input signal; and generating a critical current for allowing an MIT phenomenon to occur between the control and output terminals by using the input signal.
In some embodiments, the critical current may be that the input signal is amplified in a pulse type.
In even other embodiments of the present invention, MIT transistor systems includes: a first MIT transistor having an input terminal, an output terminal and a control terminal, and allowing MIT to occur; a second MIT transistor having an input terminal, an output terminal and a control terminal, and allowing MIT to occur; a transformer connected between the first and second MIT transistors; a pulse generator generating a signal of a pulse type; and an amplifier amplifying the signal and applying the amplified signal to the control terminal of the first MIT transistor.
In some embodiments, the transformer may be connected between the input terminal of the first MIT transistor and the control terminal of the second MIT transistor, or between the output terminal of the first MIT transistor and the control terminal of the second MIT.
The accompanying drawings are included to provide a further understanding of the present invention, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present invention and, together with the description, serve to explain principles of the present invention. In the drawings:
Preferred embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. The present invention may, however, be embodied in different forms and should not be constructed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art.
In the present disclosure, if certain devices or lines are described as being connected to a target device block, they are not only directly connected to the target device block, but also connected to the target device block by means of any other device.
Also, the same or similar reference numerals provided in each drawing denote the same or similar components. In some drawings, connection relations between devices and lines are merely shown for efficient description of the technical spirit, and therefore other devices or circuit blocks may be further provided.
Exemplary embodiments set forth herein may include complementary embodiments thereof, and it will be noted that a general operation of a metal-insulator transition (MIT) transistor may be omitted so as not to obscure the essential point of the inventive concept.
Hereinafter, it will be described about an exemplary embodiment of the present invention in conjunction with the accompanying drawings.
The MIT transistor 10 of
When a current flows through the terminal C of the MIT transistor 10, an MIT phenomenon occurs between the control terminal (terminal C) and the output terminal and then a large current flows from the input terminal (terminal I) to the output terminal (terminal O) due to the MIT phenomenon.
The MIT transistor 10 in which a discontinuous jump phenomenon appears on being turned-on is a device switching between an insulator and a metal by using the insulator (or semiconductor)-metal transition (MIT) phenomenon.
When the MIT phenomenon occurs between the control and output terminals of the MIT transistor 10, a concentration of holes doped to a control layer is required to be about nc=(0.25/a0)3. Here, a0 means the Bohr radius of a hydrogen atom. Typically, nc≈1×1018 cm˜3. A current including holes of about nc should be flowed. This current is called as a critical current ICritical current, which is a maximum current flowing through semiconductor. Therefore, it is necessary to supply the critical current for driving the MIT transistor 10.
In embodiments of the present invention, a current supplier supplying the critical current is realized as shown in
Referring to
Here, the current supplier 20 is realized with a bipolar transistor receiving a pulse input and generating the critical current.
That is, the bipolar transistor receives the pulse input with a base B. A collector C is connected to an input terminal I of the MIT transistor 10 and an emitter E is connected to the control terminal C of the MIT transistor 10.
The input terminal I of the MIT transistor 10 is connected to a power supply voltage Vcc through a first load connected between nodes n1 and n2, and the output terminal O of the MIT transistor 10 is connected to a ground voltage Vss through a second load connected between nodes n3 and n4.
In
The current supplier 20 may also be realized by using an operational amplifier.
In the end, the MIT transistor 10 may be driven by a device for supplying a critical current or an arbitrary device.
In an embodiment of the present invention, a system includes two or more devices. For example, the system of
Furthermore, the bipolar transistor or the field effect transistor, which is a current supply transistor, may be manufactured as a monolithic integrated circuit on one substrate with the MIT transistor. In addition, two transistors shown in
In addition, the current supply transistor and the MIT transistor may be included in an integrated circuit, such as an existing microprocessor, memory, or a power device like an insulated-gate bipolar transistor (IGBT).
In
Measurement conditions in
Similarly, in the drawing, a horizontal axis denotes a time and a vertical axis denotes a voltage output from a system.
When the NPN transistor 20 of
Since the measurement result waveform of
For detailed description with reference to
The transistors adopted in
In the system of
The MIT phenomenon occurs at a peak portion at which the control signal sharply rises and then a voltage instantly drops, which is due to occurrence of a negative differential resistance (NDR) phenomenon that a current is limited right after the MIT occurs and the resistance is reduced. The peak and NDR phenomenon are evidences showing occurrence of the MIT. When the peak occurs, a bottom portion signal also shows a small peak in
Under the above-described conditions, when the inlet voltage of Vinlet=7V is applied, the system of
In the drawing, a horizontal axis denotes a time, and a vertical axis denotes a voltage output from the system of
The measurement result of
The measurement conditions of
In
That is, 2N3906, which is a critical current supply transistor, is connected in the forward active mode as a general transistor. In this case, the emitter of the critical current supply transistor 23 is connected to the control terminal of the MIT transistor 10. In
An input signal from the function generator is a signal of 100 kHz, 3V, and an offset of 1.5 V, and finally 6V. An input power supply voltage at the input terminal is 4V. Vcontrol input (V) of the left axis is a signal measured at the control terminal of the MIT transistor 10. The peaks in the signal mean NDR phenomena. This NDR occurs when the MIT occurs and is an evidence of the MIT. A right axis indicates a signal measured at the output terminal. In this case, the current is about 0.3 A.
As confirmed in
Referring to
In the drawing, a horizontal axis denotes a time and a vertical axis denotes a voltage output from the system.
In
In the drawing, a horizontal axis denotes a time and a vertical axis denotes a voltage output from the system. Even when a P-type field effect transistor is used, NDR peaks can be seen in
The MIT transistor (MITR1) 10 functions as switching transistor.
An ac current generated at a secondary coil of the transformer 6 is applied to the control terminal of the MIT transistor 11.
The switching speed of the MIT transistor (MITR1) 10 is 100 kHz. The transformer 6 for high frequency operation is used which has a capacity that 1 A can flow at 10V and 100 kHz. First, the switching operation of the MIT transistor (MITR1) 10 is realized by generating a square wave of 100 kHz in a function generator 1 and supplying a critical current amplified by an amplifier 2 to the control terminal. In this case, the waveform is measured by oscilloscopes 1 and 2. The measurement result is shown in
The current induced to the secondary coil of the transformer 6 corresponds to a magnitude of the critical current for the MIT transistor. The induced current is input to the control terminal of MITR2 11. The experimental result according to an operation of the MITR2 11 is measured by oscilloscopes 3 and 4 as shown in
As shown in the oscilloscopes 3 and 4, the peaks (NDR phenomenon) mean occurrence of the MIT (see
Furthermore,
In the drawings of
Similarly, in the drawings of
As described above, according to an embodiment of the present invention, since a current supplier capable of supplying a critical current necessary for allowing an MIT phenomenon to occur in an MIT transistor is simply and efficiently provided, a smooth operation of the MIT transistor is possible.
In the specification, a current supplier is described as a transistor or a type into which a transistor and a transformer are combined, but detailed realization of the current supplier may be differed by modifying or adjusting a circuit configuration in the drawings without departing from the technical idea of the present invention.
The above-disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments, which fall within the true spirit and scope of the present invention. Thus, to the maximum extent allowed by law, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.
Number | Date | Country | Kind |
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10-2013-0078913 | Jul 2013 | KR | national |
10-2013-0156332 | Dec 2013 | KR | national |
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Number | Date | Country | |
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20150008974 A1 | Jan 2015 | US |