CN103985655B - The preparation method of the automatically controlled quantum dot of GaAs/AlGaAs semiconductor heterostructure grid and measuring method thereof - Google Patents

Abstract

The invention discloses a method for preparing GaAs/AlGaAs semiconductor heterojunction structure gate electrically controlled quantum dots. The method comprises the following steps: a. substrate growth step; b. substrate pretreatment step; c. quantum dots The preparation steps of; and d. the block encapsulation step of the quantum dot sample.

Description

Preparation method and measurement method of GaAs/AlGaAs semiconductor heterojunction gate electrically controlled quantum dots Law

technical field

The invention relates to the field of semiconductors, in particular to a method for preparing GaAs/AlGaAs semiconductor heterojunction structure grid electronically controlled quantum dots.

Background technique

With the continuous improvement of the integration level of microelectronic devices, the scale of device units is getting smaller and smaller, and the precision requirements are getting higher and higher. When the size of the electronic devices on the circuit is small to a certain extent, almost on the order of nanometers, we must consider the new physical phenomenon generated in the circuit by particle volatility, that is, the quantum effect. At this time, the traditional chip manufacturing technology and process have reached At the physical limit, quantum physics has begun to become the physical basis of nanoscale chip devices.

For the present, our crucial issue is to find the carrier that can be used to carry information in quantum information science. There are many physical systems that can provide quantum information processing, such as: linear optical devices, nuclear magnetic resonance, trapped ions, superconductivity Joseph junctions, semiconductor quantum dots, etc. At this stage, it is very difficult to say which solution is more feasible, which one is more promising, and which is most likely to realize quantum computers. Among them, the semiconductor quantum dot system is considered to be one of the material systems most likely to realize quantum computers because of its better stability and integration.

Among the many complicated quantum dot families, gate electronically controlled quantum dots have become the frontier and hot spot due to their simple electrode controllability similar to traditional silicon technology, as well as the maturity and very good integration of their micro-nano processing technology. research system.

Contents of the invention

The present invention aims at the electronically controlled quantum dot system of the semiconductor gate at the forefront of existing quantum computing research, provides a GaAs/AlGaAs semiconductor heterojunction structure gate electronically controlled quantum dot preparation method, and provides a more effective quantum dot contact (QPC) is used as the measurement method of the detection channel, and the measurement of the single electron charge and spin state in the quantum dot is realized on this structure, which provides a new carrier for the realization of quantum information on the solid-state quantum chip.

One aspect of the present invention provides a method for preparing GaAs/AlGaAs semiconductor heterojunction structure gate electrically controlled quantum dots, the method comprising the following steps:

a. Substrate growth step, wherein an undoped GaAs substrate 101, an AlGaAs buffer layer 102, an AlGaAs doped layer 103, an AlGaAs spacer layer 104 and a GaAs capping layer 105 on the surface are sequentially grown to form a stable two-dimensional electron gas structure 106;

b. substrate pretreatment step, wherein by cleaning the substrate, preferably by ultrasonic cleaning;

c. The preparation steps of quantum dots, wherein the two-dimensional electron conduction platform 100 structure is formed by etching to obtain a two-dimensional electron gas region; and then the ohmic contact electrode 200 and the metal gate are prepared by performing optical exposure, coating and metal stripping 300; Finally, by performing electron beam exposure, coating and metal stripping, the metal small electrodes 400 in the quantum dot area are obtained, forming the middle quantum dot (QD) area 500 and quantum dot contact (QPC) channel 600;

d. A block-by-block packaging step of the quantum dot sample, wherein the prepared quantum dot sample substrate is packaged.

In one embodiment of the present invention, the mass fraction of Al in the AlGaAs buffer layer 102, the AlGaAs doped layer 103 and the AlGaAs isolation layer 104 is 10% to 70%, preferably 15%-50%, and more preferably 20%-40%. , most preferably 30%.

In one embodiment of the present invention, atoms doped in the AlGaAs doped layer 103 are Si atoms, and the doping concentration is 0.5-2.0×10 ¹⁸ /cm ³ . Preferably 0.7-1.5×10 ¹⁸ /cm ³ , more preferably 0.9-1.2×10 ¹⁸ /cm ³ , most preferably 1.0×10 ¹⁸ /cm ³ .

In one embodiment of the present invention, the GaAs substrate 101 has a thickness of 300-800 nm, preferably 400-600 nm, more preferably 450-550 nm, most preferably 500 nm.

In one embodiment of the present invention, the thickness of the AlGaAs buffer layer 102 is 5-25 nm, preferably 8-20 nm, more preferably 10-18 nm, most preferably 15 nm.

In one embodiment of the present invention, the thickness of the AlGaAs doped layer 103 is 15-25 nm, preferably 17-23 nm, more preferably 18-22 nm, most preferably 20 nm.

In one embodiment of the present invention, the thickness of the AlGaAs isolation layer 104 is 30-80 nm, preferably 35-70 nm, more preferably 40-60 nm, most preferably 50 nm.

In one embodiment of the present invention, the GaAs capping layer 105 has a thickness of 3-15 nm, preferably 5-13 nm, more preferably 7-11 nm, and most preferably 10 nm.

In one embodiment of the present invention, in the substrate pretreatment process, the solutions used successively are trichlorethylene (TCE), acetone (ACE), isopropanol (IPA), deionized water (DI), ultrasonic The time is 20-180s, preferably 40-120s, more preferably 50-80s, most preferably 60s.

In one embodiment of the present invention, in the preparation stage of quantum dots, the etching solution is 98% H ₂ SO ₄ : 30% H ₂ O ₂ : H ₂ O, with different ratios, the etching speed for GaAs is 5nm/s to 40nm/s, preferably 10nm/s-30nm/s, more preferably 15nm/s-25nm/s, most preferably 20nm/s. The total etching depth is 200nm-300nm. Preferably 220nm-280nm, more preferably 230nm-260nm, most preferably 240nm.

In one embodiment of the present invention, in the preparation stage of quantum dots, the photoresist used is AZ5214, and the baking temperature is 80-110°C, preferably 85-105°C, more preferably 90-100°C, most preferably 95°C, The baking time is 50-180s, preferably 60-120s, more preferably 80-100s, most preferably 90s.

In one embodiment of the present invention, in the preparation stage of quantum dots, the metal selected for the ohmic contact electrode 200 is (10-30nm) Ni+(100-200nm) AuGe, preferably (15-25nm) Ni+(120-180nm) AuGe, More preferably (16-22nm) Ni+(135-165nm) AuGe, most preferably 20nmNi+150nm AuGe.

In one embodiment of the present invention, the high temperature annealing conditions are: temperature 350-550°C, annealing 1-10min, preferably temperature 370-500°C, annealing 2-7min, more preferably temperature 400-460°C, annealing 3-5min, The most preferred is 420°C, annealing for 5min.

In one embodiment of the present invention, in the preparation stage of quantum dots, the annealing protective gases H ₂ and N ₂ preferably contain 10-30% H ₂ , more preferably 15-25%, most preferably 20% H ₂ .

In one embodiment of the present invention, in the preparation stage of the quantum dots, the metal selected for coating the metal gate 300 is Ti+Au or Cr+Au, preferably (5nm-15nm)+(50nm-150nm), more preferably (8nm- 12nm)+(80nm-120nm), most preferably 10nm+100nm.

In one embodiment of the present invention, the electron beam exposure glue used in the preparation stage of quantum dots is double-layer PMMA950A2 glue, and the glue baking temperature is 160-200 ℃, preferably 170-190 ℃, most preferably 180 ℃, and the glue baking time For 3-10 minutes, preferably 4-8 minutes, most preferably 5 minutes, the coating metal selected by the quantum dot area metal small electrode 400 is Ti+Au, preferably (2nm-10nm) Ti+(25nm-60nm) Au, more preferably ( 4nm-8nm)Ti+(35nm-33nm)Au, most preferably 5nmTi+45nmAu, and the metal small electrode 400 is connected to the tip of the metal gate 300.

In one embodiment of the present invention, in the preparation stage of quantum dots, the electrode width of the small metal electrode 400 is 10-50 nm, preferably 20-40 nm, most preferably 30 nm.

In one embodiment of the present invention, the central quantum dot (QD) region 500 has a diameter of 200-400 nm, preferably 220-300 nm, most preferably 250 nm.

In one embodiment of the present invention, the quantum point contact (QPC) channel 600 has a width of 200-350 nm, preferably 220-300 nm, most preferably 270 nm.

Another aspect of the present invention also provides a method for measuring the charge filling of the GaAs/AlGaAs semiconductor heterojunction structure gate electrically controlled quantum dot charge. By applying a certain amount of DC bias negative voltage on each metal gate 300, a potential well that can trap electrons can be formed by using the electric field potential in the two-dimensional electron gas region, thereby forming a quantum dot (QD) region 500 and a quantum dot In the contact (QPC) channel area 600, the Coulomb blocking effect of quantum dot electron tunneling and the tunneling process of electrons can be observed through the two measurement methods of the quantum dot source-drain transport signal and the quantum dot contact channel induction signal, thereby completing Measurement and Characterization of Electron Filling States in Quantum Dots. In the measurement stage of quantum dots, the sample is placed in a very low temperature and strong magnetic field environment, the temperature is T<1K, the low frequency AC voltage is output by a lock-in amplifier (lock-in830), the AC signal amplitude is generally 4 ~ 50uV, and the DC bias The voltage is output using four DC ports of a lock-in amplifier (lock-in830).

The advantage of the present invention is that: the combined overlay of the photolithographic mask technology and the electron beam exposure mask technology provided by the present invention, as well as the electron beam coating and metal stripping technology, etc., its process is relatively simple, and can be processed in a short time. In-house batch quantum dot sample preparation. In addition, this gate electronically controlled quantum dot has strong controllability, and can complete a series of experiments based on electronic charge detection and manipulation in the solid-state semiconductor quantum dot system.

Description of drawings

Figure 1 is a schematic diagram of the structure of a two-dimensional electronic conduction platform etched on a GaAs/AlGaAs heterojunction substrate;

2 is a schematic diagram of the GaAs/AlGaAs semiconductor heterojunction structure gate electrically controlled quantum dot structure of the present invention;

Fig. 3 is the cross-sectional view of the GaAs/AlGaAs semiconductor heterojunction structure gate electrically controlled quantum dot structure cut along the A-A line of the present invention;

Fig. 4 is a schematic diagram of the innermost quantum dot region structure in Fig. 2 of the present invention;

Fig. 5 is the production process flowchart of the present invention;

FIG. 6 is a measurement graph of an example of electron tunneling process in a single quantum dot.

FIG. 7 is a measurement graph of electron tunneling process in a single quantum dot in another example.

detailed description

In order to describe the present invention more clearly, the present invention will be introduced in detail below in conjunction with the accompanying drawings.

In a specific embodiment of the present invention, a method for preparing GaAs/AlGaAs semiconductor heterojunction structure gate electrically controlled quantum dots is provided, the method includes the growth of a GaAs/AlGaAs heterojunction substrate, the heterojunction substrate Pretreatment, the preparation stage of quantum dots and the block encapsulation of quantum dot samples, the specific steps are as follows:

(1) Substrate growth: using the method of molecular beam epitaxy (MBE), sequentially grow an undoped GaAs substrate 101, an AlGaAs buffer layer 102, an AlGaAs doped layer 103, an AlGaAs isolation layer 104, and a GaAs capping layer 105 on the surface , thus forming a stable two-dimensional electron gas structure 106;

(2) Substrate pretreatment: through ultrasonic cleaning in sequence of different solutions, the substrate reaches a clean level suitable for the next step, and the substrate needs to be pretreated before etching or metal electrode preparation;

(3) The preparation stage of quantum dots: through photolithography mask technology, using wet etching technology, make two-dimensional electronic conduction platform 100 structure, obtain the two-dimensional electron gas region we need; then use photolithography mask Film engraving technology, electron beam coating and metal stripping, to prepare ohmic contact electrodes 200 and metal grids 300; finally, electron beam exposure overlaying technology, electron beam coating and metal stripping, to obtain small metal electrodes 400 in the quantum dot area , forming a quantum dot (QD) region 500 and a quantum dot contact (QPC) region 600 in the middle;

(4) Sub-block encapsulation of quantum dot samples: Use a glue-spinning machine to spin the photoresist on the completed sample substrate at a speed of 2000r/min, then cut it into small pieces with a diamond knife for encapsulation and to be measured .

The invention proposes a method for preparing GaAs/AlGaAs semiconductor heterojunction structure gate electronically controlled quantum dots, including GaAs/AlGaAs heterojunction substrate growth, GaAs/AlGaAs heterojunction substrate pretreatment, and preparation of quantum dots The stage and block encapsulation of quantum dot samples, the specific steps are as follows:

(1) Growth of GaAs/AlGaAs heterojunction substrate: using molecular beam epitaxy (MBE), sequentially grow undoped GaAs substrate 101, AlGaAs buffer layer 102, AlGaAs doped layer 103, AlGaAs spacer layer 104 and The GaAs capping layer 105 on the surface forms a stable two-dimensional electron gas structure 106, wherein the mass fraction of Al in the AlGaAs buffer layer 102, the AlGaAs doped layer 103 and the AlGaAs isolation layer 104 is 30%. , the atoms doped in the AlGaAs doped layer 103 are Si atoms, the doping concentration is 1.0×10 ¹⁸ /cm ³ , the GaAs substrate 101, the AlGaAs buffer layer 102, the AlGaAs doped layer 103, the AlGaAs isolation layer 104 and the GaAs cap layer The thicknesses of 105 are 500nm, 15nm, 20nm, 50nm and 10nm respectively, and the specific substrate hierarchy is shown in Figure 3;

(2) Pretreatment of GaAs/AlGaAs heterojunction substrate: successively use trichlorethylene (TCE), acetone (ACE), isopropanol (IPA), and deionized water (DI) solutions to treat the above prepared substrate Cleaning and ultrasonic time are both 1 minute, so that the substrate can reach a clean level suitable for the next step, and the substrate needs to be pretreated before etching or electrode preparation;

(3) The preparation stage of quantum dots: the structure and manufacturing process shown in Figure 1, Figure 2 and Figure 5, through photolithography mask technology, using wet etching technology, using etching solution 98% H ₂ SO ₄ :30%H ₂ O ₂ :H ₂ O=2:25:150, the etching speed to GaAs is 20nm/s, and the two-dimensional electronic conduction platform 100 with a depth of 240nm is etched out to obtain the two-dimensional electron conduction platform 100 we need. Dimensional electron gas area, and then perform optical exposure overlay on the six end points of the two-dimensional electron conduction platform 100, use photoresist AZ5214, bake the glue at 95°C for 90 seconds, use photolithographic mask overlay technology, and expose Out of six ohmic contact windows 201, 202, 203, 204, 205, 206, conduct electron beam coating and metal lift-off, respectively deposit 20nmNi and 150nmAuGe, and use protective gas 20% _H2 and 80% _N2 to rapidly anneal at 420°C For 3 minutes, the ohmic electrode penetrates downward, forming good contact with the two-dimensional electron gas region 106, forming ohmic contact electrodes 201, 202, 203, 204, 205, 206; Expose the window of the required metal grid 300, use electron beam evaporation coating and metal stripping, deposit 10nm Ti and 100nm Au to form the metal grid 300, clean the substrate again, and use double-layer PMMA950A2 glue as the electron beam exposure glue, After baking glue at 180°C for 5 minutes and 10 minutes respectively, conduct electron beam mask exposure of the small structure of the quantum dot area, use electron beam evaporation coating and metal stripping, deposit 5nm Ti and 45nm Au, and make metal small electrodes 400, metal small electrodes The line width of the electrode is 30nm, and the end of each small metal electrode 400 is connected with the tip of the corresponding metal gate 300 made above, so that a quantum dot region 500 structure is formed in the middle, and its quantum dot center (QD) The region 500 has a diameter of 250 nm and forms a quantum dot contact (QPC) channel region with a channel width of 270 nm, as shown in FIG. 4 .

(4) Block encapsulation of quantum dot samples: put the AZ5214 photoresist with a thickness of 1.4um on the quantum dot sample substrate produced above at a speed of 2000r/min on the glue-spinning machine, and use 95°C on the glue-baking machine The temperature is baked for 90s, and then cut into small pieces with a diamond knife for packaging and measurement.

The present invention also provides a measurement method for GaAs/AlGaAs semiconductor heterojunction structure gate electronically controlled quantum dots, using weak signal measurement technology, by applying a negative voltage on each metal gate 300, and using an electric field potential, the two-dimensional The electron gas region forms a region where electrons can be trapped, that is, the quantum dot region 500 and the quantum dot contact channel 600. Through the two measurement methods of quantum dot transport signal and quantum dot contact induction, the Coulomb of quantum dot electron tunneling can be observed. Blocking effects and real-time processes of single-electron tunneling.

The single quantum dot sample structure made by the present invention, as shown in FIG. The voltage on the metal grid 300 is directly equivalent to being applied to the small metal electrode 400 , forming a quantum dot (QD) region 500 and a quantum dot contact (QPC) channel 600 in the middle. The experimental samples were measured in an extremely low temperature T<0.5K environment. The AC voltage during the measurement was input using a lock-in amplifier (lock-in830), and the DC bias voltage applied to each metal grid was input using a lock-in amplifier (lock-in 830). -in830) DC port output. By selecting two ohmic electrodes 201 and 204, one end applies a voltage of V _AC = 20uV, the other end uses a lock-in amplifier to measure the channel current I, and a negative voltage is applied to the middle selected metal small electrodes 402 and 403, through which the measurement channel The size of the current I can control the tunneling of electrons between the quantum dot region 500 and the quantum dot contact channel 600, and the control intensity can be completely cut off from the current almost conducting to the electronic tunneling, and selecting one can make the quantum dot 500 and the quantum dot contact The voltage at which the channel 600 is completely cut off is applied to the small metal electrodes 402 and 403 . Then re-select the ohmic contact electrodes 203 and 204, apply a voltage of Vac=20uV at one end, and measure the current size I passing through the other end. By adjusting the size of the negative voltage applied on the small metal electrodes 404 and 406, it can be well controlled. The tunneling rate between the quantum dot 500 and the electron pool in the source-drain ohmic contact electrodes 203 and 204, when the applied negative voltage is negative enough, and the tunneling rate is at megahertz, then the small metal electrode 405 selected in the middle, when Control the negative voltage of the small metal electrode 405 to increase continuously, and the electrons will be discharged from the quantum dots one by one, so that an oscillating current signal can be observed, which we call the Coulomb blocking effect. As shown in Figure 6(a), electrons jump from the electron pool of the source ohmic contact electrode 203 to the electron pool of the drain ohmic contact electrode 204 through the quantum channel of the quantum dot 500, thereby forming a continuous electron gap between In the tunneling process, what is observed experimentally is that the current passing through the quantum dot 500 will change significantly when the current changes with the DC voltage applied by the small metal electrode 405, and each peak in the curve represents the current in the quantum dot 500. An energy level is provided for electrons to tunnel between the source and drain electrodes, thereby completing the detection of electron tunneling process in quantum dots and the characterization of electron filling.

In addition, we can adjust the resistance of the quantum dot contact channel 600 by applying a DC bias voltage on the metal small electrode 401, so that its resistance is 20-100 kiloohms, which is the most sensitive for detecting the electron tunneling process in the quantum dot. Area. We can also observe the real-time tunneling process of electrons by observing the current change of the quantum point contact (QPC) channel (Fig. 6(b)). The specific measurement spectrum is shown in Fig. 6. The position of each peak in (a) is relative to In the figure (b), there will be a process of sudden jumping of the current, and the two are in one-to-one correspondence, which means that the quantum dot contact (QPC) channel can indirectly observe the tunneling of electrons in the quantum dot through induction. This detection method has the effect of not destroying the electronic state of the quantum dot 500 system itself.

Existing experimental research mainly stays at the stage of quantum transport research, that is to say, it stays in the way of measuring continuous current. Our invention not only provides an adjustable quantum dot 500 system (by changing the structure and diameter of the small metal electrodes forming the quantum dot 500, etc., the size of the quantum dot can be well controlled, especially can be very Good control of the number and mode of electron filling in the quantum dot), and provide a new sample structure and measurement method using the quantum dot contact 600 as a detection channel. In addition, the coupling strength between the quantum dot contact channel 600 and the quantum dot 500 we invented and designed is adjustable. The coupling strength between them can be adjusted from zero to a larger strength region, which allows us to complete the experimental detection of different coupling strengths experimentally. These are lacking and imperfect in the existing experimental techniques.

The quantum dot preparation method described in the present invention can also obtain high-quality experimental samples for experimental research when different preparation parameters are changed. As shown in Figure 7, it is an experimental measurement curve of another quantum dot sample prepared by changing the width and arrangement of the small metal electrodes 400, and then changing the size and shape of the two channels of the quantum dot contact 600 and the quantum dot 500. . The diameter of the quantum dot 500 is 300nm, and the width of the quantum dot contact channel 600 is 320nm. The curve shown in Figure 7, (a) also shows that as the voltage of the small metal electrode becomes more and more negative, the electrons in the quantum dots (QD) 500 are emptied one by one, and the change of the current is to see Coulombs one by one Oscillating peaks, similarly (b) shows that the current differential change of the quantum dot contact (QPC) 600 corresponds to the current peak in (a), indicating that the quantum dot contact 600 can perfectly detect the filling and state of electrons in the quantum dot. The difference between the two samples in Figure 7 and Figure 6 is that the quantum dot sample shown in Figure 7 has more electrons that can be filled in the quantum dots, which can be explained from the greater number of Coulomb peaks that can be observed in Figure 7, In addition, it can be clearly seen that the voltages of the small metal electrodes required to evacuate the electrons in the quantum dots are also completely different, which shows that after changing some of the above parameters, the manufacturing method of our invention can still obtain a very Good experimental samples, providing various high-quality quantum dot samples for solid-state quantum computing research based on semiconductor quantum dot chip research.

The above-mentioned embodiments are only descriptions of preferred implementations of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, those skilled in the art may make various modifications to the technical solutions of the present invention. and improvements, all should fall within the scope of protection of the claims of the present invention.

Claims (10)

1. a preparation method for the automatically controlled quantum dot of GaAs/AlGaAs semiconductor heterostructure grid, Said method comprising the steps of:

A. substrate growth step, grows plain GaAs substrate (101), AlGaAs the most successively Cushion (102), AlGaAs doped layer (103), AlGaAs separation layer (104) and surface GaAs cap (105), thus form stable two-dimensional electron gas structure (106)；

B. substrate pre-treatment step, wherein cleans the substrate；

C. the preparation process of quantum dot, wherein by being etched into Two-dimensional electron conducting platform (100) Structure, obtains the twodimensional electron gas region in described two-dimensional electron gas structure (106)；Pass through again into Row optical exposure, plated film and metal-stripping, prepare Ohm contact electrode (200) and be positioned at surface Metal gates (300)；Finally by carrying out electron beam exposure, plated film and metal-stripping, obtain quantum The metal small electrode (400) in some region, forms middle quantum dot (QD) region (500) and quantum Point cantact (QPC) passage (600), described metal small electrode (400) and metal gates (300) Tip be connected；

D. the piecemeal encapsulation step of quantum dot sample, the quantum dot sample substrate wherein preparation completed enters Row encapsulation.

2. the GaAs/AlGaAs automatically controlled amount of semiconductor heterostructure grid as claimed in claim 1 The preparation method of son point, wherein said AlGaAs cushion (102), described AlGaAs doped layer (103) mass fraction of Al is each independently 10% and in described AlGaAs separation layer (104) To 70%.

3. GaAs/AlGaAs semiconductor heterostructure grid electricity as claimed in claim 1 or 2 The preparation method of control quantum dot, the atom that wherein said AlGaAs doped layer (103) is adulterated is Si, Doping content is 0.7 × 10¹⁸/cm³To 1.2 × 10¹⁸/cm³；And/or described GaAs substrate (101) Thickness is 300nm-800nm；And/or described AlGaAs cushion (102) thickness is 5nm-25nm； And/or described AlGaAs doped layer (103) thickness is 15nm-25nm；And/or described AlGaAs The thickness of separation layer (104) is 30nm-80nm；And/or described GaAs cap (105) thickness For 3nm-15nm.

4. the GaAs/AlGaAs automatically controlled amount of semiconductor heterostructure grid as claimed in claim 1 The preparation method of son point, wherein in described substrate preprocessing process, the solution successively used is respectively Trichloro ethylene (TCE), acetone (ACE), isopropanol (IPA), deionized water (DI)；And/or Wherein at the preparatory phase of described quantum dot, wet etching liquid is 98%H₂SO₄: 30%H₂O₂: H₂O, Etching speed to GaAs is 5nm/s to 50nm/s, and total etching depth is 180nm-300nm； And/or the preparatory phase at described quantum dot, the roasting glue temperature of photoresist is 80 DEG C to 110 DEG C, roasting glue Time is 50 seconds to 180 seconds；And/or wherein at the preparatory phase of described quantum dot, Ohmic contact electricity The thickness that metal is Ni+AuGe+Ni, Ni that pole (200) plated film is selected is 10-30nm, AuGe Thickness be 100-250nm；And/or wherein at the preparatory phase of described quantum dot, Ohm contact electrode (200) annealing conditions is 350 DEG C to 550 DEG C, and the time is 1-10min.

5. the GaAs/AlGaAs automatically controlled quantum of semiconductor heterostructure grid as claimed in claim 1 The preparation method of point, wherein at the preparatory phase of described quantum dot, Ohm contact electrode (200) moves back Fire protective gas is H₂And N₂, wherein contain H₂Volume ratio be 10-30%；And/or wherein in amount The preparatory phase of son point, the metal that metal gates (300) plated film is selected is Ti+Au or Cr+Au, The thickness of Ti or Cr be the thickness of 5-15nm, Au be 50-150nm；And/or wherein at quantum dot Preparatory phase, the roasting glue temperature of electron beam exposure glue is 160 DEG C to 200 DEG C, and the roasting glue time is 3 Minute to 10 minutes.

6. the GaAs/AlGaAs automatically controlled quantum of semiconductor heterostructure grid as claimed in claim 1 The preparation method of point, wherein at the preparatory phase of quantum dot, the electrode width of metal small electrode (400) Degree is 10-50nm.

7. the GaAs/AlGaAs automatically controlled quantum of semiconductor heterostructure grid as claimed in claim 1 The preparation method of point, wherein at the preparatory phase of quantum dot, the plated film choosing of metal small electrode (400) It is 25-75nm with the thickness that the thickness that metal is Ti+Au, Ti is 2-10nm, Au.

8. the GaAs/AlGaAs automatically controlled quantum of semiconductor heterostructure grid as claimed in claim 1 The preparation method of point, wherein a diameter of 200-400nm of quantum dot (QD) central area (500).

9. the GaAs/AlGaAs automatically controlled amount of semiconductor heterostructure grid as claimed in claim 1 The preparation method of son point, wherein the channel width (600) of quantum point contact (QPC) is 200-350nm.

10. a GaAs/AlGaAs semiconductor heterostructure grid automatically controlled quantum dot electric charge is filled Measuring method, wherein by each metal gates (300) upper applying direct current biasing negative voltage, two Form potential well in dimensional electron gas region, thus it is logical to form quantum dot region (500) and quantum point contact Region, road (600), transports signal measurement method by the leakage of quantum point source or quantum point contact passage senses The coulomb blockade effect of signal measurement method observation quantum point-like electron tunnelling and the tunnelling process of electronics, from And complete the measurement of electronics occupied state in quantum dot.