Bottom solution residue prevention sample holder for vertical tellurium-cadmium-mercury liquid phase epitaxial growth

Abstract

The utility model discloses a bottom solution residue prevention sample holder for vertical tellurium-cadmium-mercury liquid-phase epitaxial growth, which belongs to the field of infrared semiconductor material preparation and comprises a conical flow guide base, a micro-groove array, a SiC / SiO2 super-lyophobic functional layer and a thermal gradient regulation and control module. During working, the frame body is preheated, the melt flows back along the chamfer surface under the action of gravity during lifting, the micro-grooves generate capillary force for directional diversion, the super-lyophobic layer reduces the adhesion work, and the thermal gradient inhibits solution solidification. By applying the sample holder, the residual quantity of a melt can be greatly reduced, the defect density of an epitaxial layer is reduced, the available area is increased to more than 95%, and the problem of millimeter-scale particle residue in the traditional LPE growth is solved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to infrared semiconductor material preparation field especially relates to the sample holder of preventing bottom solution residual for vertical tellurium cadmium mercury liquid phase epitaxial growth. BACKGROUND

[0002] In the growth process of tellurium cadmium mercury LPE, the substrate needs to be repeatedly immersed in the mercury-containing molten solution. When the traditional plane sample holder is pulled, the bottom edge is easy to form millimeter-sized granular residues (diameter 10-30 mm) due to the surface tension of the solution. The residues become defect sources in subsequent high-temperature treatment, leading to problems such as protrusions on the epitaxial layer surface, stress lines or pits around the protrusions, smaller available area of epitaxy, and larger size of derived cutting. UTILITY MODEL CONTENT

[0003] To solve the technical problems in the background art, the utility model provides a sample holder for preventing bottom solution residual for vertical tellurium cadmium mercury liquid phase epitaxial growth.

[0004] The technical solution of the utility model is as follows:

[0005] The sample holder for preventing bottom solution residual for vertical tellurium cadmium mercury liquid phase epitaxial growth comprises:

[0006] The conical flow guide base is provided with a 60° chamfered surface at the bottom edge, and the chamfered surface is subjected to laser polishing treatment (surface roughness Ra≤0.1 μm);

[0007] The micro-groove array is distributed on the chamfered surface and comprises four grooves with a depth of 2 mm and a pitch of 7.33 mm, and the groove depth-width ratio is 0.67;

[0008] The super-lyophobic functional layer is composed of a SiC bottom layer (thickness 500 nm) deposited by chemical vapor deposition and a SiO2 surface layer (thickness 200 nm) sputtered by a magnetron.

[0009] The thermal gradient control module comprises a micro-heater and a temperature sensor embedded in the base, and the power density of the heater is ≥50 W / cm 2 .

[0010] In the above technical solution, the cross section of the micro-groove is V-shaped, and the groove wall inclination angle deviation from the parallelism of the chamfered surface is ≤0.5°.

[0011] In the above technical solution, the SiO2 surface layer is in an amorphous state, the X-ray diffraction spectrum half-width is ≥5° (2θ angle), and the surface contact angle is 152°±3°.

[0012] In the technical scheme, the micro heater is a serpentine platinum resistance wire with a line width of 100 μm, a spacing of 200 μm, and covering more than 80% of the projection area of the base.

[0013] In the technical scheme, the temperature sensor is a K-type thermocouple with a measuring point being 0.5 mm away from the surface of the base and a response time being less than 0.1 s.

[0014] In the technical scheme, the conical flow guide base is made of molybdenum alloy (thermal expansion coefficient 4.8×10 -6 / ℃), and the included angle between the chamfered surface and the horizontal plane is 60°±0.5°.

[0015] In the technical scheme, a 100 nm thick Cr transition layer is arranged between the SiC bottom layer and the molybdenum alloy base.

[0016] A semiconductor epitaxial system integrates the sample holder and is configured with:

[0017] A temperature closed-loop control unit adjusts the power of the heater according to the feedback of the temperature sensor.

[0018] A lifting mechanism has a verticality precision of ≤0.1°.

[0019] In the technical scheme, the temperature closed-loop control unit sets the temperature difference ΔT between the holder and the melt to be 4℃±0.5℃.

[0020] The plating structure of the anti-bottom solution residue sample holder for vertical tellurium cadmium mercury liquid phase epitaxial growth is that the proportion of the crystal face orientation of the SiC bottom layer is ≥90%.

[0021] Advantages:

[0022] 1. Zero residue growth:

[0023] The triple residue prevention mechanism (gravity drainage + capillary flow + super-lyophobicity) reduces the residue amount of the melt, and avoids surface protrusions and stress defects caused by residues during high-temperature processing.

[0024] 2. Improved epitaxial quality:

[0025] The surface defect density of the epitaxial layer is reduced, the effective epitaxial area is greatly improved, and the material cutting loss is reduced.

[0026] 3. Strong process compatibility:

[0027] The temperature control precision of the thermal gradient module is ±0.5℃, which is suitable for the growth temperature window; the SiC / SiO2 composite plating layer is resistant to high-temperature corrosion, and the service life is improved. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of the utility model.

[0029] Figure 2 The experimental result physical picture of the unimproved sample rack.

[0030] Figure 3 The experimental result physical picture of the improved sample rack of the utility model.

[0031] Among them, the conical flow guide base 1, the chamfered surface 2, the groove 3, the super-lyophobic functional layer 4 and the thermal gradient control module 5. DETAILED DESCRIPTION

[0032] The utility model will be described in detail below in combination with the drawings and specific embodiments. However, the following embodiments are only used to explain the utility model, and the protection scope of the utility model should include the whole content of the claims, and through the description of the following embodiments, the person skilled in the art can fully realize the whole content of the claims of the utility model.

[0033] Embodiment 1: Sample rack manufacturing and structure.

[0034] I. The manufacturing process of the anti-bottom solution residual sample rack for vertical tellurium cadmium mercury liquid phase epitaxial growth is as follows:

[0035] Step 1, base processing:

[0036] Select molybdenum alloy blank, and form the base by wire cutting;

[0037] Process 60° chamfered surface (height 3mm) on the edge of the base, and adopt picosecond laser polishing (wavelength 1064nm, pulse energy 0.5mJ) to make the surface roughness Ra=0.08μm;

[0038] Mill 4 V-shaped micro grooves (depth 2mm, upper opening width 3mm, interval 7.33mm) on the chamfered surface, and the groove wall parallelism deviation is 0.3° to the chamfered surface.

[0039] Step 2, plating layer preparation:

[0040] Vacuum evaporate 100nm thick Cr transition layer (deposition rate 0.2nm / s);

[0041] Chemical vapor deposition SiC bottom layer:

[0042] Reaction gas: SiH4 / CH4 / H2=1:1:10 (volume ratio);

[0043] Deposition temperature 800℃, pressure 10kPa, thickness 500nm;

[0044] Magnetron sputtering SiO2 layer:

[0045] Target material: high-purity SiO2 (99.999%), sputtering power 300W;

[0046] Ar / O2=20:1, thickness 200 nm, grain size 30±5 nm.

[0047] Step 3, heating module integration:

[0048] Etching a serpentine channel (0.5 mm deep, 100 μm wide) on the back of the base;

[0049] Embedding a platinum resistance wire (diameter 80 μm) and filling with Al2O3 insulating paste;

[0050] Implanting a K-type thermocouple (diameter 0.2 mm) at 0.5 mm from the surface.

[0051] II. Structure of a sample holder for preventing bottom solution residue for vertical HgCdTe liquid phase epitaxy growth includes:

[0052] Conical flow guide base 1: the bottom edge is provided with a 60° chamfered surface 2, which is subjected to laser polishing treatment (surface roughness Ra≤0.1 μm);

[0053] Microgroove array: distributed on the chamfered surface, including 4 grooves 3 with a depth of 2 mm and a pitch of 7.33 mm, the groove aspect ratio is 0.67;

[0054] Super-lyophobic functional layer 4: covering the surface of the base and the grooves, composed of a SiC bottom layer (thickness 500 nm) deposited by chemical vapor deposition and a SiO2 surface layer (thickness 200 nm) sputtered by a magnetron;

[0055] Thermal gradient control module 5: including a micro-heater and a temperature sensor embedded in the interior of the base, the power density of the heater is ≥50 W / cm 2 .

[0056] Example 2: epitaxial growth comparison experiment.

[0057] Experimental group: using the sample holder of the utility model (ΔT=4℃), the experimental result physical diagram is as shown in Figure 2 .

[0058] Control group: traditional flat sample holder (without chamfer / groove / plating layer), the experimental result physical diagram is as shown in Figure 3 .

[0059] Table 1: comparison of experimental results of experimental group and control group

[0060]

[0061] Test process:

[0062] Melt preparation: HgCdTe solution is placed in a graphite crucible, the temperature is 465℃;

[0063] Sample holder preheated to 469℃ (ΔT=4℃), loaded with CdZnTe substrate (10x10mm);

[0064] Vertical pulling (speed 1mm / min, angle deviation 0.2°), pulling height 50mm;

[0065] After cooling, detection:

[0066] Residual amount: Hg element content on the surface of the base measured by ICP-MS; Defect analysis: confocal microscope scanning the epitaxial layer; Stress test: X-ray diffraction rocking curve half-peak width.

[0067] From the comparison results of the above table 1 and Figure 2 and Figure 3 It can be seen from the comparison results that the improved sample holder structure of the utility model can greatly reduce the melt residual amount, reduce the defect density of the epitaxial layer, and improve the available area, solving the problem of millimeter-level particle residue in the traditional LPE growth.

[0068] The above description is merely a specific implementation of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A sample holder for preventing bottom solution residue for vertical liquid phase epitaxy growth of tellurium cadmium mercury, characterized by, Comprise: Conical flow guide base: the bottom edge is provided with a 60° chamfer surface, and the chamfer surface is subjected to laser polishing treatment; Micro-groove array: distributed on the chamfer surface, comprising 4 grooves with a depth of 2 mm and a pitch of 7.33 mm, and a groove aspect ratio of 0.67; Super-lyophobic functional layer: covering the surface of the base and the groove, composed of a SiC bottom layer by chemical vapor deposition and a SiO2 surface layer by magnetron sputtering; Thermal gradient regulation module: comprising a micro-heater and a temperature sensor embedded in the base.

2. The sample holder of claim 1, wherein, The cross section of the micro-groove is V-shaped, and the inclination angle of the groove wall is parallel to the chamfer surface with a deviation of ≤0.5°.

3. The sample holder of claim 1, wherein, The SiO2 surface layer is in an amorphous structure, the X-ray diffraction spectrum half-width is ≥5°, and the surface contact angle is 152°±3°.

4. The sample holder of claim 1, wherein, The micro-heater is a serpentine platinum resistance wire with a line width of 100 μm, a pitch of 200 μm, and covering more than 80% of the projected area of the base.

5. The sample holder of claim 1, wherein, The temperature sensor is a K-type thermocouple with a measuring point 0.5 mm away from the surface of the base and a response time <0.1 s.

6. The sample holder of claim 1, wherein, The conical flow guide base adopts a molybdenum alloy base body, and the chamfer surface and the horizontal plane form an angle of 60°±0.5°.

7. The sample holder of claim 6, wherein, A 100 nm thick Cr transition layer is arranged between the SiC bottom layer and the molybdenum alloy base body.

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