CN106698333A

CN106698333A - Ordered transfer method of precinct epitaxial nanopillar arrays

Info

Publication number: CN106698333A
Application number: CN201710028756.0A
Authority: CN
Inventors: 李俊泽; 李沫; 龙衡; 王文杰; 张健
Original assignee: Institute of Electronic Engineering of CAEP
Current assignee: Institute of Electronic Engineering of CAEP
Priority date: 2017-01-16
Filing date: 2017-01-16
Publication date: 2017-05-24

Abstract

The invention discloses an ordered transfer method of precinct epitaxial nanopillar arrays aiming to acquire nanopillar array epitaxial slice by performing MOCVD (metalorganic chemical vapor deposition) or MBE (molecular beam epitaxy) precinct epitaxial on an open-hole graphical sapphire substrate with SiO2 as a mask, wherein the nanopillar arrays grow identically along the vertical direction and are distributed uniformly and tidily. The nanopillar arrays are transferred extensively and orderly after the nanopillar arrays are solidified by adopting polydimethylsiloxane and an SiO2 mask layer is etched through a buffer oxide etching agent; the ordered transfer method has the advantages that technological requirements on equipment are low, the arrays are kept ordered and tidy and the like, and nanopillar materials are kept at the bottom and the top, so that the nanopillar materials can be used for preparing electrodes or bonded to other flexible substrates conveniently, and wider application of the nanopillar array materials is benefited.

Description

A kind of orderly transfer method of selective area epitaxial nano column array

Technical field

The invention belongs to nanometer material science and technology and low-dimensional field of photoelectric devices, relate to the use of SiO₂As mask A kind of nano column array that selective area epitaxial is formed, and in particular to orderly transfer method of selective area epitaxial nano column array.

Background technology

, compared to two-dimensional layer material, with big table body ratio, high surface area, the ratio of width to height can for the 3-D nano, structures such as nano-pillar Adjust, the characteristic such as the size cycle is adjustable, can be used for the function elements such as photocatalytic water, biomedical detection, sensor, new energy devices, Therefore opto-electronic device etc., also turn into international research focus.

The preparation method of current nano-pillar is divided into two kinds of big classifications：From top to bottom（top-down）From bottom to top （bottom-up）.Top-to-bottom method is mainly by the side such as nano impression, electron beam lithography, deep-UV lithography, nanometer bead Formula coordinates etching and corrosion technology to realize；Mode from bottom to top mainly passes through self-organizing growth and mask selective area epitaxial reality Existing, difference is whether the arrangement of nanostructured is random, and whether growth pattern is also according to having catalyst etc. to distinguish to have segmented.This The nano-pillar preparation method that is directed to of invention is to be obtained using preparing open cell type nano-patterned substrate and carry out MOCVD selective area epitaxials Even and proper alignment nano column array.

It is by the graphic sapphire with mask generally to obtain nano column array with the mode of above-mentioned MOCVD selective area epitaxials Substrate is realized, but the electric conductivity of Sapphire Substrate can directly prepare various devices insufficient for large-area nano post array Part, other application needs to be transferred to and prepared in flexible substrate, the function element such as such as nano generator, it is therefore desirable to shift Semiconductor nano column material.Existing some means can obtain nano-pillar, such as tweezers etc. from epitaxial wafer and scratch or molten Ultrasound and filtered with copper mesh and obtain nano-pillar in liquid, but this mode is unordered, loses the advantage of nano column array, also Limit integrated in nano column array use and specific micro-nano device in a wider context.In addition, directly using nano-pillar Array epitaxial wafer is that the process bands such as electrode preparation are come difficult, it is necessary to the photoetching process for passing through Nano grade coordinates essence through mask layer Accurate electrode is prepared and could completed, and undoubtedly further increases technology difficulty.Therefore, a kind of large-area nano post array turns in order Shifting method is to realizing and extends the application of nanometer column material and plays an important role.

The content of the invention

It is in band open cell type mask pattern the invention provides a kind of orderly transfer method of selective area epitaxial nano column array Change in Sapphire Substrate on the basis of selective area epitaxial nano column array, by dimethyl silicone polymer （Polydimethylsiloxane, PDMS）With buffer oxide etchant（Buffer oxide etch, BOE solution）Corrosion The orderly transfer method of large-area nano column material array is realized in the cooperation of liquid, and the method overcomes substrate to answer nanometer column material With limitation, the orderly sexual clorminance for extending the range of application of nanometer column material and keeping it to arrange.Compared to being solidified with PDMS merely The demoulding, the nano material part in corrosion liquid energy retaining holes type mask also for follow-up nano-pillar electrode design or is bonded to other Backing material reduction technology difficulty.

Technical scheme is as follows：

A kind of orderly transfer method of selective area epitaxial nano column array, it is characterised in that comprise the following steps：

1）Prepare nanometer column material selective area growth epitaxial wafer

The substrate of epitaxial wafer is band open cell type SiO₂The Sapphire Substrate of mask, mask thicknesses are 70-150 nanometers, periodic regime 1 ~ 3 microns, using MOCVD（MOCVD）Or molecular beam epitaxy（MBE）Complete nano-pillar constituency After extension, at 300 ~ 800 nanometers, highly at 5 ~ 20 microns, being formed, there is single nanometer column diameter periodic arrangement uniformly to receive Rice post array.

2）Spin coating solidifies PDMS

In one layer of PDMS prepolymer of epitaxial wafer surface spin coating, the thickness of PDMS prepolymers is highly determined according to nano-pillar, typically extremely Less less than 1 micron at the top of nano-pillar；The epitaxial wafer that spin coating there are PDMS prepolymers then is put into vacuum to be kept for 50-90 minutes, is made PDMS is obtained to be fully contacted and discharge the bubble in mixed liquor with nano column array；Finally epitaxial wafer is put on hot plate, is kept 90-135 DEG C, heat 1-2 hours, the PDMS prepolymers in selective area epitaxial nanometer column material are fully cured, PDMS is uniformly filled In nano column array space, PDMS solidification polymers are formed, in parcel nano-pillar material protection nano column array knockout course Integrality and order.

3）Corrosion substrate masks layer

The epitaxial wafer that PDMS solidifications will be completed is put into ready BOE solution and carries out wet etching, because SiO₂Mask layer with Corrosive liquid it is insufficient contact, it is therefore desirable to more etching times are about 5-7 minutes；Substrate masks layer is corroded, reservation is covered Nanometer column material in fenestra is that subsequent electrode prepares or be bonded to other flexible substrate provides convenients.

4）Clean and the demoulding

Epitaxial wafer is taken out from corrosive liquid, with alcohol washes, then is repeated with deionized water and rinsed well, removal BOE is rotten Erosion liquid, and dried up it with nitrogen gun；PDMS solidification polymers are taken off from epitaxial wafer surface, you can obtain large-area ordered row Row nano column array.

Beneficial effects of the present invention are as follows：

The present invention, by solidification parcel nanometer column material, coordinates the removal of BOE solution using PDMS prepolymers infiltration nano column array SiO₂Mask layer, and the demoulding obtains the orderly transfer of large-area nano column material, can be effectively retained the orderly of nano column array Property and integrality；A nanometer column material is directly obtained compared to direct PDMS glue, the present invention weakens nanometer using BOE removal mask layers The bond strength of column material and substrate, increased the integrality of nanometer column material transfer while nanometer material in remaining mask aperture Material, prepares and provides operating space to be bonded to other backing materials or electrode；In view of the Sapphire Substrate conduction of epitaxial wafer is led Hot property is poor, and this branch mode can overcome substrate to follow-up technogenic influence, and can be bonded to flexible substrate.

Brief description of the drawings

Fig. 1 is the side structure schematic view of selective area epitaxial nano column array epitaxial wafer in the present invention.

Fig. 2 is the overlooking the structure diagram of selective area epitaxial nano column array epitaxial wafer in the present invention.

Fig. 3 is spin coating in the present invention, after solidification PDMS polymer epitaxial wafer side structure schematic view.

Fig. 4 for the present invention in use BOE solution corrosions SiO₂The side structure schematic view of epitaxial wafer after mask layer.

Fig. 5 is the nano column array schematic side view after the demoulding in the present invention.

Wherein, reference is：101 is Sapphire Substrate, and 102 is SiO₂Mask layer, 104 is nano-pillar, and 207 is PDMS Layer.

Specific embodiment

Further to illustrate the present invention to reach technological means and effect that predetermined goal of the invention is used, below in conjunction with Legend illustrates specific embodiment of the invention.Following examples are used to illustrate the present invention, but are not limited to model of the invention Enclose.

As shown in figure 1, epitaxial wafer is the nano column array of uniform proper alignment, substrate is with SiO₂The figure of mask layer Change Sapphire Substrate.Wherein 101 is Sapphire Substrate, and 102 is SiO₂Mask layer, 104 is to carry out selective area epitaxial by MOCVD to obtain The nano column array for obtaining.

Fig. 2 SEM（SEM）102 is SiO in top view₂Mask layer, 104 is nanometer column material.By SEM Test determines mask layer（102）Thickness and nano column array（104）Height and cycle.

As shown in figure 3, spin coating solidification dimethyl silicone polymer（PDMS）, i.e. 207 in Fig. 3：

Step 1. determines PDMS according to 104 height measured in Fig. 1 by PDMS colloid prepolymer volumes and whirl coating platform rotating speed Prepolymer thickness, its principle is PDMS colloids（207）Thickness is less than nano column array（104）About 1 micron of height.

Step 2. then puts it into vacuum and is kept for 50-90 minutes so that PDMS colloids（207）With nano column array （104）It is fully contacted and discharges the bubble in mixed liquor.

Step 3. puts on hot plate epitaxial wafer, is kept for 90-135 DEG C, heats 1-2 hours, makes selective area epitaxial nano-pillar PDMS prepolymers in material are fully cured.

As shown in figure 4, corrosion substrate masks layer.The sample that PDMS solidifications will be completed is put into ready buffer oxide leaching Erosion agent（Buffer oxide etch, BOE solution）Wet etching is carried out in solution, etching time is about 5-7 minutes.Corrode Substrate masks layer（In Fig. 3 102）, the nanometer column material of reservation is located at the part in mask aperture, i.e. shown in 104 in Fig. 3.

As shown in figure 5, cleaning and the demoulding.By sample from corrosive liquid taking-up alcohol washes, entered repeatedly with deionized water Row is rinsed well, removes BOE corrosive liquids, and dried up it with nitrogen gun.PDMS solidification polymers are taken off from epitaxial wafer surface, Can obtain by PDMS colloids（207）Protect large-area ordered arrangement nano column array（104）.

Claims

1. a kind of orderly transfer method of selective area epitaxial nano column array, it is characterised in that：Comprise the following steps：

Step 1：Prepare in band open cell type SiO₂In the Sapphire Substrate of mask, prepared using MOCVD or MBE selective area epitaxials Nano column array epitaxial wafer, and measure it highly；

Step 2：Height spin coating PDMS prepolymers according to nano column array, the thickness of PDMS prepolymers is at least below nanometer capital 1 micron of portion；Then epitaxial wafer is put into carries out pumping process in vacuum, thoroughly the bubble in removal mixture；Finally by extension Piece is heated, and keeping temperature is 90-135 DEG C, and the heat time is 1-2 hours, and PDMS prepolymers are fully cured；

Step 3：Corrosion substrate Si O₂Mask layer, BOE corrosive liquids are soaked in 5-7 minutes by epitaxial wafer, remove SiO₂Mask layer, with Weaken the bonding strength of nanometer column material and substrate, while retaining the nanometer column material in mask aperture；

Step 4：Epitaxial wafer is taken out from BOE corrosive liquids, is cleaned with deionized water with alcohol successively, then dried up, then taken off PDMS prepolymers obtain nano column array, realize the orderly transfer of large-area nano post array, and retain nano-pillar top with Bottom material, is conveniently bonded to other materials or prepared by electrode.

2. the orderly transfer method of a kind of selective area epitaxial nano column array according to claim 1, it is characterised in that：It is described SiO₂The thickness of mask is 70-150 nanometers, 1 ~ 3 micron of periodic regime.

3. the orderly transfer method of a kind of selective area epitaxial nano column array according to claim 1, it is characterised in that：It is single At 300 ~ 800 nanometers, highly at 5 ~ 20 microns, some single nano-pillars are formed has periodic arrangement uniform to the diameter of nano-pillar Nano column array.

4. the orderly transfer method of a kind of selective area epitaxial nano column array according to claim 1, it is characterised in that：Step The epitaxial wafer after spin coating PDMS prepolymers is put into vacuum in 2 carries out pumping process, is kept for 50-90 minutes so that PDMS with receive Rice post array is fully contacted and discharges the bubble in mixed liquor.

5. the orderly transfer method of a kind of selective area epitaxial nano column array according to claim 1, it is characterised in that：Step Drying is dried up using nitrogen in 4.