KR20050081125A - Two-qbit quantum computing gate - Google Patents

Abstract

The present invention relates to two quantum bit quantum computational gates, and in order to achieve the above object, a method of the present invention provides a source, a drain and a line width of several tens of nanometers or less on an upper silicon layer of a silicon on insulator (SOI) substrate Forming a conducting channel to form a double quantum dot and side gates spaced apart by tens of nanometers in a vertical direction, doping the remaining portions except the quantum dots, and then forming a gate oxide film, and a two-dimensional conduction channel Forming a control gate for producing an electron gas layer and a conventional metallization process. A key feature of the device's core operation is the entangled phenomena of the ground states and spin intrinsic states of each quantum dot in a system consisting of spins of two coupled quantum dots under magnetic field changes. And a device designed to perform quantum computation as desired using the superposition or uncertainty principle.

Description

Two-Qbit Quantum Computing Gate

Quantum computation refers to a series of technologies that process information in a fundamentally different way by using uncertainty, overlap, entanglement, and interference, which are intrinsic features of quantum mechanics. As these sizes get smaller, these new features appear in microclocks, making it impossible to communicate information at all without eavesdropping, or to the computing power of a classic computer, the computer we are using now. It means opening up new horizons in information processing technology, such as solving problems that never existed.

The behavior of the computers we are using can be described by the Turing machine, a mathematical ideal model (A. Turing, Proc. Lond. Math. Soc. 42 , 230 (1937)). Are all irreversible. An irreversible operation inevitably generates heat. The beginning of this technology was Bennioff after Bennett (CH Bennett, IBM J. Res. Dev. 6, 525) proposed a reversible Turing machine in 1973 that could perform operations like an irreversible Turing machine. ) Pointed out that reversible operations can be made with quantum systems that are time-reversible, and Richard Pineman introduced the concept of quantum computers for the first time in 1982. Since then, a specific quantum turing machine model was proposed by Deutsch three years later. But quantum computing became the decisive factor in the 1994 implementation of the prime factorization method, published by Bell's Sho in 1994, and the 1997 implementation of quantum computers by nuclear magnetic resonance. The prime factorization method has the potential to break all modern ciphers in use around the world, along with data retrieval solutions published by Grover of the same institute three years later. Similar to the show's algorithm, Gruber's data retrieval solution finds one in N data, which can be done in (N) ^1/2 times as opposed to a conventional computer requiring N / 2 attempts. For example, if you find a 56-bit cryptographic key randomly without difficult factorization, it takes about 1000 years for a conventional computer but about 4 minutes for a quantum computer. Representatively researched method so far is nuclear magnetic resonance method, nuclear magnetic resonance quantum computer has a relatively long coherence time, and all kinds of experimental techniques have been developed, compared to other quantum methods. Implementation is advantageous. But it has a fatal flaw that it is impossible to integrate. Recently, a method using a quantum dot [10], a resonator cavity QED [11], a Josephson element [12], and the like have been proposed. To this end, the present invention intends to present a structure and a method for manufacturing a conditional NOT double quantum bit, as well as a single quantum bit operator essential for the general purpose gate implementation in quantum operation. In addition, by using CMOS technology, which is widely used in the implementation of quantum gates, this paper suggests a method capable of highly integrated mass production without a drastic change in the production process, compared to other nuclear magnetic resonance methods.

According to the present invention, the following technical achievements are essential to meet the above technical requirements and to develop a high-capacity, ultra-fast quantum parallel processing, and highly integrated two quantum bit quantum gate. Applying CMOS process and electron beam lithography to form side gates in tens of nanometer intervals and vertical directions on both sides of a conducting channel of several tens of nanometers in width, and to independently control the spin of electrons in quantum dots 1 and 2 The process of forming the upper gate required by the electron beam lithography method and spaced apart from the quantum dots at appropriate intervals calculated, and the appropriate parameters for selectively doping the remaining side gate and source drain except the quantum dots to be locally formed in the conduction channel. And processes are necessary.

The double quantum bit quantum computational gate of the present invention is formed on a silicon on insulator (SOI) substrate, and the structure of the device is the source (3) on the upper silicon layer on the silicon double oxide film (2) on the underlying silicon substrate (1). And a negative electrical repulsive force applied to the side gates 1 and 6 and the side gates 2 and 7 in the direction perpendicular to the conductive channel on the same plane. Quantum dots (8, 9) are formed in the conduction channel, and then the gate oxide film (10) is formed in a conventional manner, and finally the control gate is responsible for inducing and controlling the two-dimensional electron gas layer in the conduction channel. When (11) is formed, the completion of the double quantum bit quantum gate which is the object of the present invention is achieved.

A method of manufacturing a double quantum bit quantum gate of the present invention will be described in detail with reference to the accompanying drawings.

The part used for fabricating double quantum bit quantum gate in SOI substrate is upper layer silicon of appropriate thickness.

First, by the electron-beam direct writing method, the side gates 1 and side gates 2 and 10 in the vertical direction with respect to the source 3, the drain 4, and the conduction channel 5 of several to several tens of nanometers wide. After patterning (6, 7)

Reactive ion etching (RIE) is used to remove all remaining upper silicon (Figure 2).

Subsequently, the doping mask is patterned and developed using a negative electron beam resist and lithography method to dope the remaining silicon layer except the center portion of the conductive channel where the quantum dots 8 and 9 are formed, and used as a doping mask. The doping process is performed (Fig. 3)

After that, the lamination process of the gate oxide film 10 having the appropriate thickness of several nanometers is performed.

After the process, the control gate 11 is patterned to a size sufficient to cover two quantum dots by using a photolithography method, followed by etching and metallization by other suitable methods.

After the conventional CMOS process is completed, the completion of the present double quantum bit quantum computation gate is achieved (Fig. 1).

Firstly, the expected effects of the completion of the double quantum bit quantum computation gate are similar to those of the conventional CMOS process in the manufacturing method, thereby enabling not only large-scale integration that has emerged as a fundamental and practical problem of the existing quantum gate devices. It has been reported that multi-bit operation is much easier, and that the ability of prime factorization by Shaw's algorithm and data retrieval by Guru's method is superior to the so-called God's ability. It is already being studied in advanced countries in terms of national security. Therefore, the practical implementation of the present dual quantum bit quantum computation gate is important enough to be a crossroad of national security beyond the effect of the present invention.

1 is a perspective view illustrating two quantum bit quantum gates according to the present invention;

Figure 2 is a perspective view showing the completion of the silicon oxide film process of the two quantum bit quantum gate silicon nano device according to the present invention,

3 is a diagram conceptually illustrating a double quantum dot that is the core of two quantum bit quantum gate silicon nano devices according to the present invention.

Explanation of symbols for the main parts of the drawings

1: silicon substrate

2: silicon oxide film

3: source

4: drain

5: conduction channel

6: side gate 1

7: side gate 2

8: QD1

9: quantum dot 2

10: gate oxide film

11: control gate

Claims (6)

In the structure and operation of two quantum bit quantum gates, Side gates 1 and vertically formed on the center of the conductive channel connecting the source and the drain to the top-Si layer of the silicon-on-insulator (SOI) substrate in a vertical direction with a distance of several tens of nanometers due to appropriate parameters. Two quantum bit quantum computational gates characterized by a structure in which side gates 2 are located, and then control gates in a conventional CMOS process are located on the gate oxide layer Defining a source, a drain, and a side gate connected by conducting channels of several to several tens of nanometers wide for the fabrication of the two quantum bit quantum computation gates using an ultrafine pattern of a method suitable for upper layer silicon; Etching the micro pattern to form an active region and side gates in the upper layer silicon; Forming a gate oxide film over the substrate; Stacking a material to be used as a control gate on the front surface of the substrate and processing the same into a suitable form; In the operating characteristics of the device completed by the process of claim 2, Two quantum bit quantum gates, characterized in that the quantum dot formation method of the conduction channel is based on the negative electrical potential applied to the side gate, In the position and role of the side gate 1 and side gate 2 during the process of claim 2, The side gate 1 and the side gate 2 are staggered from each other in the opposite direction of the conduction channel, and the side gate 1 acts as an interaction between the two quantum dots and acts as a quantum gate, and the side gate 2 is more at the edge portion of the two quantum dots. Two quantum bit quantum gates, characterized by implementing the same sized quantum dots due to the formation of a clear tunnel barrier and the application of an appropriate potential, In the operating characteristic of claim 4, Two quantum bit quantum gates, characterized in that the spins in the two quantum dots are exchanged with each other as the spin exchange J between the two quantum dots is changed by appropriate external magnetic field change and side gate 1 adjustment, The method according to claim 2, Ultrafine pattern means two quantum bit quantum gates, including electron beam direct drawing and self-assembly or any other possible method,