Background technique
As the IC chip of hyundai electronics Information Technology Foundation, Component units are silicon base CMOS field effect transistorPipe, has the characteristics that function is strong, low in energy consumption, speed is fast and at low cost by the IC chip that CMOS is formed.Initial tensNian Zhong, integrated circuit follow Moore's Law substantially, i.e., the number that component can be accommodated on each 18~24 months integrated circuits increasesIt doubles, performance is also deducted a percentage one times, but is limited since processing technology relatively lags behind with device physics after entering 21 century, siliconThe development of base CMOS transistor will reach its physics limit.Intel Company announces within 2015, abandons silicon in 7nm technology node,Other channels are found instead of material, develop new semiconductor integrated circuit technology, related semiconductor material include GaAs,The materials such as InP, SiC, AlN, Nano diamond, carbon nanotube, graphite.Although these materials carrier mobility with higherWith normal carrier mean free path, but the reason of be limited to micro Process compatibility and convenience, there is no any one to takeBecome the leading material of semiconductor devices for silicon.Carrier will necessarily meet with ceaselessly lattice collisions when transmitting in solid-state materialAnd scattering, so that ballistic transport is destroyed, so the structure and working principle of solid-state devices determine it on power and frequencyDevelopment is limited.
Electronics is transmitted without lattice scattering in a vacuum, and transmission rate theoretically can reach 3 × 1010Cm/s, and partly leadTransmission rate in body only has 3 × 107Cm/s, therefore compared with semiconductor transistor, the carrier transport of radio tube is specialProperty there is great superiority, but since vacuum electron device is seriously hampered by backward manufacturing process, so vacuum tube is depositedVolume is larger, operating temperature is high, switch low-response and is difficult to the disadvantages of integrated.With micro-processing technology and vacuum electron device systemStandby technology develops, and is applied to the micro-processing technology to prepare vacuum electron device and has become possibility, the vacuum channel transistor of preparationHas the characteristics that speed height and anti-radiation.Minimum additionally, due to its characteristic size, electron-transport, theoretically can be with apart from extremely shortWithout the high vacuum seal of traditional vacuum device, electronics collision less transport is realized in low vacuum even atmospheric condition environment, is hadPreferable comprehensive advantage.
When in the early 1960s, present micrometer-nanometer processing technology not yet occurs, Stanford Research Institute, the U.S. is mentionedSwitching speed is gone out 10-10The micron order size vacuum tunnel-effect device concept of s magnitude, based on micro vacuum deviceDevelop vacuum integrated circuit.Nineteen sixty-eight Spindt is developed micro- based on Mo and Si using top-down semiconductor microactuator processing methodThe field emission cathode array of pointed cone, so that micro vacuum triode becomes possibility, vacuum electron device enters " micro- since thenReceive " epoch.Vacuum integrated circuit is successfully had developed within 1985, in 1mm2Area in manufactured 10000 micro vacuum tubes.The Han etc. of NASA Ames Lab in 2012 proposes the concept of nano vacuum channel triode, utilizes optical lithography and ionBody incinerator technology prepares the air duct triode cutoff frequency with insulator separation grid structure and is up to 0.46THz, simultaneouslyA series of work of subsequent nano vacuum channel triodes is led.The implementation method of nanoscale vacuum channel transistor includesTwo-dimensional electron gas transmitting and low-dimensional carbon material thermionic emission in field emission, Schottky diode etc..
But solid-state transistor in the prior art causes it on power and frequency due to its structure and working principleDevelopment is limited, and carrier mobility and carrier mean free path are lower, it is difficult to improve；And vacuum channel transistorModulator approach and on-off ratio are single, are unfavorable for controlling.In addition, existing vacuum channel transistor that there is also response speeds is relatively slow,The problems such as emission is small is only used in the vacuum device for working in weak current, and powerful vacuum device is also unable to satisfyThe requirement of part.
In order to overcome technological deficiency of the existing technology, it is desirable to provide a kind of novel vacuum channel transistor and its systemPreparation Method.
Summary of the invention
One of the objects of the present invention is to provide a kind of vacuum channel transistors and preparation method thereof.
In order to achieve the above objectives, the present invention provides a kind of vacuum channel transistor, which successively includes anode, firstInsulating layer, grid, second insulating layer and photocathode, wherein being formed with vacuum channel between the anode and photocathode.
Preferably, the vacuum channel is through first insulating layer, grid layer and second insulating layer setting.
Preferably, the anode is conductive material or semiconductor material；Preferably, anode material is Si or Al；Preferably,Anode thickness is 300 μm~2mm.
Preferably, the grid is conductive material；Preferably, grid material Si, Al and Mo；Preferably, gateFor 10nm~10 μm.
Preferably, the photocathode includes the photocathode film of cathode substrate and formation on substrate, the photoelectricityThe material of cathode is GaN photocathode, GaAs photocathode, bialkali photocathode or multialkali photocathode.
Preferably, the photocathode film with a thickness of 40nm~3 μm.
Preferably, the vacuum channel is cylinder vacuum channel, and preferably diameter is 40nm~15 μm；Or the vacuum ditchRoad is square column type vacuum channel, and preferably side length is 40nm~15 μm.
According to another aspect of the present invention, a kind of vacuum channel transistor array is provided, wherein each transistor is as aboveThe vacuum channel transistor.
In accordance with a further aspect of the present invention, a kind of preparation method of vacuum channel transistor is provided, this method includes followingStep:
Anode material is provided；
The first insulating layer is formed in anode surface；
Grid layer is formed on the first insulating layer；
Second insulating layer is formed on the grid layer；
The second insulating layer, grid layer and first are sequentially etched absolutely using photoetching process or ion beam focusing etching technicsEdge layer is to the anode surface；
Photocathode is provided, photocathode is conformed into resulting structures surface, obtains having the photocathode of vacuum channel brilliantBody pipe.
Preferably, this method further comprises activating to the photocathode of the transistor.
Beneficial effects of the present invention are as follows:
1, the present invention provides a kind of vacuum channel transistor, and the transistor has higher carrier mobility and current-carryingSub- mean free path, there is no electron energy scatterings in solid state device to the shadow of device thermal stability in vacuum channel for electronicsIt rings, transistor has high thermal stability.
2, the present invention is using photocathode as the cathode of transistor, and the working condition of transistor is in addition to can be by being applied toOutside grid impulse on grid is controlled, it can also lead to the intensity for adjusting light source and pulse frequency is modulated, than being based onSpindt cathode, graphite is dilute and the cold cathode vacuum channel transistor of the materials such as silicon has more modulator approaches.
3, photocathode has the characteristics that dark current is small, so that the vacuum channel transistor with photocathode is with higherOn-off ratio.
4, the response time of photocathode can reach femtosecond magnitude, and working frequency can reach Terahertz frequency, the present inventionVacuum channel transistor based on photocathode can possess higher working frequency limit than other kinds of transistor, be a kind ofHigh performance vacuum electron device
Specific embodiment
In order to illustrate more clearly of the present invention, the present invention is done further below with reference to preferred embodiments and drawingsIt is bright.Similar component is indicated in attached drawing with identical appended drawing reference.It will be appreciated by those skilled in the art that institute is specific belowThe content of description is illustrative and be not restrictive, and should not be limited the scope of the invention with this.
In following description given, for purposes of illustration, in order to provide comprehensive reason to one or more embodimentSolution, numerous specific details are set forth.It will, however, be evident that these implementations can also be realized without these specific detailsMode.
Fig. 1 shows the vacuum channel transistor working principle according to the preferred embodiment of the invention based on photocathode.VeryEmpty channel transistor includes anode 1, grid 2 and photocathode 3.Photocathode is according to the cathode signal applied on it and entersIt is mapped to the intensity and frequency of the incident light hv on cathode, launching electronics e, electronics reaches anode under the action of grid signal.LightElectric cathode is a kind of excitation of light and generates the cathode of electron emission, mostly semiconductor material, is operable under room temperature, toolHave the advantages that quantum efficiency is high, emitted electron energy is concentrated, fast response time and dark current are small.The higher photoelectricity yin of quantum efficiencyPole is for example including GaAs photocathode, AlGaAs photocathode, GaN photocathode, AlGaN photocathode, InGaAs photoelectricity yinPole, CsTe photocathode, Cs3Sb photocathode, CsNa2KSb photocathode, Na2KSb photocathode and K2CsSb photocathodeDeng.The response time of photocathode can reach femtosecond magnitude, so the limit of photocathode differentiates frequency and can reach Terahertz frequencyRate is much higher than solid crystals tube device and field emission vacuum channel transistor.The photocathode of semiconductor material can use micro-Electronics processing technology carries out overlay film on photocathode surface, and can prepare vacuum channel by etching technics such as photoetching processes, makesVacuum channel transistor of the preparation based on photocathode is possibly realized.In addition the electron emission characteristic of photocathode is by incident intensityThe conditions such as degree, incident light pulse frequency, anode voltage influence, so the vacuum channel transistor based on photocathode is than other kindsThe vacuum channel transistor of class has more modulator approaches and on-off ratio.
Fig. 2 shows a kind of structural schematic diagrams of the vacuum channel transistor based on photocathode according to the present invention.CrystalPipe includes anode layer 210, the first insulating layer 220, grid layer 230, second insulating layer 204 and photocathode 250, and is formed inBetween anode and photocathode, through the vacuum channel 260 of the first insulating layer, grid layer and second insulating layer.Photocathode 250It including support substrate 251 and is cathode luminous cathode thin film 252 thereon.
Anode layer material is conductive material, can be but be not limited to the metals such as the semiconductors such as Si or Al.Anode thickness is excellentIt is selected as 300 μm~2mm.
Gate layer material is conductive material, can be but be not limited to Si, Al and Mo etc..The thickness of grid layer is preferably10nm~10 μm
Photocathode includes photocathode support substrate and the photocathode film layer that is formed thereon.Support substrate is for exampleFor glass, thickness is, for example, 0.3~5mm, and the material of photocathode film can be but be not limited to GaN photocathode, GaAsPhotocathode, bialkali photocathode or multialkali photocathode, the thickness of film are preferably 40nm~3 μm.
The material of insulating layer can be but be not limited to Al2O3Or SiO2Deng.The thickness of first insulating layer and second insulating layer10nm~15 μm are respectively preferably, the thickness of two insulating layers can be identical or not identical.
Vacuum channel is formed in two insulating layers and grid, and runs through two insulating layers and grid, is highly equal to twoThe sum of insulating layer and gate.The shape of vacuum channel can be but be not limited to cylindrical or square column type.Cylinder vacuumRaceway diameter is preferably 40nm~15 μm, and the side length of square column type vacuum channel is preferably 40nm~15 μm.
According to another embodiment of the present invention, a kind of vacuum channel transistor array is provided, including is arranged in the form of an arrayMultiple vacuum channel transistors, each transistor is with structure as described above.Such as Fig. 2 shows two to be arranged side by sideVacuum channel transistor.
According to another aspect of the present invention, a kind of preparation method of photocathode vacuum channel transistor is provided, including withLower step:
S1 is dirty using organic solvent, the organic matter of acid solution and deionized water cleaning anode material surface and oxide etc.Contaminate object；
S2 makes the first insulating layer on the resulting anode material surface of the first step；
S3 makes grid conducting layer in the first surface of insulating layer of second step resulting structures；
S4 makes second insulating layer in the Gate Electrode Conductive layer surface of third step resulting structures；
S5 makes vacuum channel in the 4th resulting multi-layer film material of step using photoetching or ion beam focusing lithographic technique；
S6 is purified and is activated to first electrode；
The 5th resulting structure of step is formed with the side of insulating layer to S7 and the photocathode film of photocathode closely pastes simultaneouslyIt is fixed, thus obtain the vacuum channel transistor according to the present invention based on photocathode.
Beneficial effects of the present invention are described in detail below with reference to specific example.
Example 1
Vacuum channel transistor based on GaAs photocathode and preparation method thereof is as follows:
The single crystal silicon material that anode material is selected as with a thickness of 0.52mm；Two insulating layers are SiO2Material, thickness are 5μm；Grid layer is Si material, with a thickness of 4 μm；Photocathode is GaAs photocathode, and cathode material is with a thickness of 3 μm, support substrateFor the glass substrate with a thickness of 5mm；Vacuum channel shape be square column type, 10 μm of side length.
Vacuum channel transistor based on photocathode the preparation method is as follows:
It is dirty using acetone, dehydrated alcohol, acid solution and deionized water cleaning silicon wafer surface organic matter and oxide etc.Contaminate object；
Silicon wafer is put into oxidation furnace, is aoxidized in silicon wafer surface and generates the first SiO2Insulating layer；
In the resulting SiO of second step2Surface grows silicon active layer；
The resulting material of third step is placed again into oxidation furnace, is aoxidized in wafer surface and generates the 2nd SiO2Insulating layer,First and second SiO2Not oxidized Si active material is the grid layer of transistor between layer；
Vacuum channel is made to silicon wafer surface in the resulting wafer surface of the 4th step using ion beam focusing lithographic technique；
It cleans and activates GaAs photocathode；
The chip architecture with vacuum channel that 5th step obtains is fitted in the resulting GaAs photocathode of the 6th stepTogether, that is, the vacuum channel transistor based on GaAs photocathode is obtained.
Fig. 3 be under 532mm illumination, when anode voltage is 10V and photocathode voltage is 0V, the vacuum channel of example 1The grid voltage control characteristic of transistor.When grid voltage is improved by 3V to 15V, the on-off ratio of transistor is greater than 104, it is a kind ofHigh performance transistor.
Example 2
Vacuum channel transistor based on GaN photocathode and preparation method thereof is as follows:
The Al material that anode material is selected as with a thickness of 1mm；Two insulating layers are Al2O3Material, thickness are 100nm；GridExtremely Mo metal material, with a thickness of 100nm；Photocathode is GaN photocathode, and cathode material is with a thickness of 80nm, glass supportSubstrate thickness is 0.46mm；Vacuum channel shape is circle, diameter 100nm.
Vacuum channel transistor based on photocathode the preparation method is as follows:
The first step cleans Al material surface organic matter and oxidation using acetone, dehydrated alcohol, acid solution and deionized waterThe pollutants such as object；
Second step prepares the first Al in Al material surface using ion sputtering deposition technology2O3Insulating layer；
Third step prepares Mo grid layer in the resulting material surface of second step using ion sputtering deposition technology；
4th step prepares the 2nd Al in the resulting material surface of third step using ion sputtering deposition technology2O3Insulating layer；
5th step makes vacuum channel Al material surface in the resulting wafer surface of the 4th step using photoetching process；
6th step cleans and activates GaN photocathode；
7th step by what the 5th step obtained there is vacuum channel chip architecture and the resulting GaN photocathode of the 6th step to pasteIt is combined, i.e. vacuum channel transistor of the acquisition based on GaN photocathode.
It is under 266mm illumination from Fig. 4, when anode voltage is 3V and photocathode voltage is 0V, the grid of transistor is electricPress control characteristic.When grid voltage is improved by 0.2V to 1V, the on-off ratio of transistor is greater than 103, equally it is a kind of high performanceTransistor.
The present invention uses photocathode as the cathode of vacuum channel transistor, effectively increases the work frequency of transistorRate, and possess the working condition of voltage and light source two ways control transistor, it is a kind of ideal high-frequency and high efficiencyTransistor.
Obviously, the above embodiment of the present invention be only to clearly illustrate example of the present invention, and not be pairThe restriction of embodiments of the present invention may be used also on the basis of the above description for those of ordinary skill in the artTo make other variations or changes in different ways, all embodiments can not be exhaustive here, it is all to belong to this hairThe obvious changes or variations that bright technical solution is extended out are still in the scope of protection of the present invention.