US-20260127471-A1 - QUANTUM INFORMATION PROCESSING DEVICE

US20260127471A1US 20260127471 A1US20260127471 A1US 20260127471A1US-20260127471-A1

Abstract

The first layer includes a first gate electrode array disposed in the first direction to control the qubits of the qubit string, and a second gate electrode array disposed in the first direction to control the inter-qubit interaction of the interaction string. The second layer includes a third gate electrode array disposed in the second direction, and a fourth gate electrode array disposed in the second direction adjacently to the third gate electrode array. The third and the fourth gate electrode arrays control a part of the multiple qubits, and a part of the multiple inter-qubit interactions, respectively.

Inventors

Noriyuki LEE
Ryuta Tsuchiya
Digh Hisamoto

Assignees

HITACHI, LTD.

Dates

Publication Date: 20260507
Application Date: 20241106
Priority Date: 20190805

Claims (20)

1 . A quantum information processing device, comprising: a fin; a first layer provided on the fin; and a second layer provided on the first layer, wherein the first layer includes a first gate electrode array extending in a first direction to control qubits and a second gate electrode array extending in the first direction to control inter-qubit interactions, the second layer includes a third gate electrode array extending in a second direction different from the first direction and a fourth gate electrode array extending in the second direction and disposed adjacent to the third gate electrode array, a protruding portion is provided in parts of the third gate electrode array and the fourth gate electrode array, and the protruding portion is in contact with the fin through a gate insulating film.
2 . The quantum information processing device according to claim 1 , wherein the protruding portion controls some of the qubits and some of the inter-qubit interactions as an electrode array.
3 . The quantum information processing device according to claim 2 , wherein the electrode array is provided discretely in the second direction so as to two-dimensionally extend the number of qubits.
4 . The quantum information processing device according to claim 1 , wherein the protruding portion is in contact with the fin in a portion of the first layer where the first gate electrode array and the second gate electrode array are not formed.
5 . The quantum information processing device according to claim 1 , further comprising: a conduction wire array provided in the second direction on the second layer to apply a high frequency signal to the qubits.
6 . The quantum information processing device according to claim 5 , further comprising: a magnet array provided in the second direction on the conduction wire array to apply a static magnetic field to the qubits.
7 . The quantum information processing device according to claim 1 , further comprising: an initialization gate electrode provided below the fin to initialize the qubits.
8 . The quantum information processing device according to claim 1 , wherein the first direction and the second direction cross each other.
9 . The quantum information processing device according to claim 8 , wherein the first direction is a vertical direction, and the second direction is a horizontal direction.
10 . The quantum information processing device according to claim 1 , wherein, when performing a gate operation on the qubits, a qubit to be controlled is selected using a gradient of a magnetic field.
11 . The quantum information processing device according to claim 1 , wherein, when performing a gate operation on the qubits, a qubit to be controlled is selected by selecting a conduction wire to which an RF pulse is applied.
12 . The quantum information processing device according to claim 1 , wherein, when performing a gate operation on a plurality of qubits, a control bit and a target bit are selected by controlling a gradient of a magnetic field or a voltage applied to a gate electrode.
13 . The quantum information processing device according to claim 1 , wherein, when performing a gate operation on a plurality of qubits, a direction in which the qubits to be controlled are arranged is controlled by selecting a conduction wire to which an RF pulse is applied or by controlling a voltage applied to a gate electrode.
14 . The quantum information processing device according to claim 1 , wherein, when reading out the qubits, conversion from spins of the qubits to the number of electrons is performed by controlling a voltage applied to a gate electrode.
15 . A qubit array, comprising: a fin; and a plurality of gate electrode arrays provided on the fin, wherein the fin has a two-dimensional planar shape, and includes a first fin having a shape extending in a first direction so that qubits interact in the first direction and a second fin having a shape extending in a second direction different from the first direction so that some of the qubits interact in the second direction.
16 . The qubit array according to claim 15 , wherein, in the two-dimensional planar shape, the number of second fins is smaller than the number of first fins.
17 . The qubit array according to claim 15 , wherein, in the two-dimensional planar shape, the fin has a lattice shape extending in the first direction.
18 . The qubit array according to claim 15 , wherein a protruding portion of a part of a gate electrode array extending in the first direction is provided on the second fin.
19 . A qubit array, comprising: a fin; and a plurality of gate electrode arrays provided on the fin, wherein the fin has a lattice shape extending in a first direction.
20 . A method for manufacturing a qubit array, comprising: a first step of forming a fin of semiconductor on a first insulator layer; a second step of forming a gate insulating film on the fin; a third step of forming, on the gate insulating film, a qubit control gate of semiconductor extending in a first direction and an interaction control gate of semiconductor extending in the first direction; a fourth step of removing a part of the qubit control gate extending in the first direction; and a fifth step of forming, on the fin exposed by the removal, a qubit control gate of semiconductor extending in a second direction different from the first direction and an interaction control gate of semiconductor extending in the second direction.

Description

TECHNICAL FIELD The present invention relates to a quantum information processing device. BACKGROUND ART Currently, aiming at implementation of quantum computers, research has been proceeded by many groups on a global scale. Experiments have been carried out using various physical systems. Whichever the physical system the group employs, it is necessary for implementing the quantum computer to allow the isolated system that never conducts material exchange nor energy exchange with the external environment to generate qubits, and to maintain coherence of the quantum system for an extended period of time. For the purpose of causing the qubits to serve as the quantum computer, it is essential not only to pursue performance of the single qubit, but also to construct the device that contains multiple qubits. As one of the reported cases concerning multi-quantum bit integration of the semiconductor qubit (for example, see patent literature 1), there is the single qubit structure which is simply extended in the lateral direction. In the structure, many electrodes are vertically arranged, to which a DC voltage is applied to control the qubit state and the interaction between the qubits. The number of the electrodes in the foregoing structure, however, increases as the increase in the number of qubits. Upon operation at an extremely low temperature in the refrigerator, the number of electrodes which allow external application of DC voltages and RF pulses is limited. This may restrict the number of the qubits that can be increased. When qubits are two-dimensionally added planarly to the structure having the qubits linearly arranged one-dimensionally, there is no place for accommodating controlling electrodes. Accordingly, it is impossible to make the structure practicable. It is therefore difficult to make the qubits into two-dimensional planar array by simply extending the qubit structure through the conventionally proposed process. It has been well known that two-dimensional extension is required to make the qubits serving in the quantum computer. The qubit string structure adapted to the requirement has been proposed (for example, see patent literature 2). It is intended to individually control the two-dimensionally extended qubit strings through switching with the wiring and the transistor, which are formed on the upper layer. CITATION LIST Patent Literature Patent Literature 1: WO Publication No. 2009/072550Patent Literature 2: Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2018-532255 SUMMARY OF INVENTION Technical Problem If the qubit having the lower layer with complicated structure is added to the qubit string structure as disclosed in patent literature 2, the resultant structure fails to securely maintain crystallinity in the upper layer of the substrate. Accordingly, it is difficult for the current semiconductor manufacturing method to form the transistor on the upper layer. It is an object of the present invention to provide the quantum information processing device which allows two-dimensional qubit extension using the current semiconductor manufacturing method. Solution to Problem The quantum information processing device according to an embodiment of the present invention includes a fin, a first layer formed on the fin, and a second layer formed on the first layer. The fin includes a qubit string having multiple qubits arranged in a row in a first direction, and an interaction string having multiple inter-qubit interactions arranged in a row in the first direction. The qubit string and the interaction string are alternately arranged in a second direction that is different from the first direction. The first layer includes a first gate electrode array disposed in the first direction to control the qubits of the qubit string, and a second gate electrode array disposed in the first direction to control the inter-qubit interaction of the interaction string. The second layer includes a third gate electrode array disposed in the second direction, and a fourth gate electrode array disposed in the second direction adjacently to the third gate electrode array. The third and the fourth gate electrode arrays control a part of the multiple qubits, and a part of the multiple inter-qubit interactions, respectively. Advantageous Effects of Invention An embodiment of the present invention provides the quantum information processing device which allows two-dimensional qubit extension using the current semiconductor manufacturing method. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a bird's eye view of a qubit string that constitutes the quantum information processing device. FIG. 2 is a plan view of a quantum information processing device. FIG. 3 is a plan view of a quantum information processing device. FIG. 4A is a plan view representing a method of manufacturing the qubit strings that constitute the quantum information processing device. FIG. 4B is a sectional view A representing