There are more than 200 silicon carbide crystal types in the world, among which the mainstream crystal type of current silicon carbide wafer production is 4H-SiC. Below specification of 100mm silicon carbide in PAM-XIAMEN are available:
1. Specifications of 100mm Silicon Carbide 4H N-type
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Specificationsof Silicon Carbide N-type 100mm Diameter – |
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| polytype | 4H-SiC |
| A type | N-type SiC substrate |
| Resistance | 0.015 – 0.028 ohm * cm |
| surface orientation | Off-Axis-misorientation: 4.0˚ towards [11-20] ± 0.5˚ |
| Diameter | 100.0 mm + 0.0 / -0.5 mm |
| Thickness | 350.0 µm ± 25.0 µm |
| The length of the main cut | 32.5 mm ± 2.0 mm |
| The length of the secondary cut | 18.0 mm ± 2.0 mm |
| Orthogonal disorientation | ± 5.0˚ |
| Orientation main cutoff | [11-20] ± 5.0˚ |
| The orientation of the secondary cut | 90.0˚ clockwise relative to the main shear ± 5.0˚, working up the side plate (Si side) |
| Surface quality | Reverse: an optical polishing, the working party: the chemical-mechanical polishing, epi-ready (ready for epitaxy) |
| (MPD) Density of micropores type defects | – |
| Ultra-low density of defects such as micropores | ≤1 / cm2 |
| (BPD) Basal planar dislocation | ≤1500 / cm2 |
| Full thickness variation (TTV) | ≤15 µm |
| curvature of plate | ≤45 µm |
| The local thickness variation per 1 cm2 | m ≤4 |
| The absence of stacking faults | + |
| Lack hexagonal inclusions | + |
| Absence of carbon inclusions | > 99% 4H polytype |
| product class | |
| Boundary chipped / recess under diffuse illumination | width and depth of ≥ 0,5 mm not allowed |
| The total gross area of the defect,determined using a microscope at 200X ⃰ | ≤ 10% of the area |
| Furrow / band under diffuse illumination | not allowed |
| The field of foreign polytype under diffuse illumination ⃰ | ≤5% area |
| Stains and other contaminants in the light of high intensity | not allowed |
| Cracks in the light of high intensity | not allowed |
| Defects in the form of hexagonal structures with high light intensity ⃰ | the total area of ≤10% |
| Scratches length determined by confocal microscopy Lasertec | total ≤ 150 mm |
| * Exception – a distance 3mm from the edge of the plate | |
2. Specifications of Semi-insulating Silicon Carbide,100 mm Diameter
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The plates of the semi-insulating silicon carbide 100 mm diameter. – 8 pcs. |
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| Polytype | 4H-SiC |
| A type | Semi-insulating SiC substrate of high purity |
| Resistance | ≥1E6 ohm * cm |
| surface orientation | On-Axis: (0001) ± 0.25˚ |
| Diameter | 100.0 mm + 0.0 / -0.5 mm |
| Thickness | 500.0 µm ± 25.0 . µm |
| The length of the main cut | 32.5 mm ± 2.0 mm |
| The length of the secondary cut | 18.0 mm ± 2.0 mm |
| Orthogonal disorientation | – |
| Orientation main cutoff | [11-20] ± 5.0˚ |
| The orientation of the secondary cut | 90.0˚ clockwise relative to the main shear ± 5.0˚, working up the side plate (Si side) |
| Surface quality | Back side: optical polishing, the working party: the chemical-mechanical polishing, epi-ready (ready for epitaxy) |
| (MPD) Density of micropores type defects | standard |
| Ultra-low density of defects such as micropores | – |
| (BPD) Basal planar dislocation | – |
| (TTV) Full thickness variation | ≤15 µm |
| Curvature of plate | ≤45 µm |
| The local thickness variation per 1 cm2 | ≤ 4 µm |
| The absence of stacking faults | + |
| Lack hexagonal inclusions | + |
| Absence of carbon inclusions | > 99% 4H polytype |
| Product class | |
| Boundary chipped / recess under diffuse illumination | width and depth of ≥ 0,5 mm not allowed |
| The total gross area of the defect, | ≤ 10% of the area |
| determined using a microscope at 200X ⃰ | |
| Furrow / band under diffuse illumination | not allowed |
| The field of foreign polytype under diffuse illumination ⃰ | ≤5% area |
| Stains and other contaminants in the light of high intensity | not allowed |
| Cracks in the light of high intensity | not allowed |
| Defects in the form of hexagonal structures with high light intensity ⃰ | the total area of ≤10% |
| Scratches length determined by confocal microscopy Lasertec | total ≤ 150 mm |
| * Exception – a distance 3mm from the edge of the plate | |
3. Electrical Characteristics of Silicon Carbide
Silicon carbide properties in electrical aspect are superior than that of silicon:
3.1 High voltage resistance:
The breakdown electric field of 100mm silicon carbide wafer is 10 times stronger than silicon. The device made of a silicon carbide substrate can greatly Improve the withstand voltage capacity, operating frequency and current density, and greatly reduce the conduction loss of the device.
3.2 High temperature resistance:
At higher temperature, semiconductor devices will produce intrinsic excitation of carriers, causing device failure. The greater the band gap, the higher the limit operating temperature of the device. The silicon carbide band gap is close to 3 times that of silicon, which can ensure the reliability of silicon carbide devices under high temperature conditions. Generally, the maximum operating temperature of silicon devices cannot exceed 300°C, but the limit operating temperature of silicon carbide devices can reach 600°C or more. At the same time, the silicon carbide thermal conductivity is higher than that of silicon. The high thermal conductivity helps silicon carbide devices to dissipate heat, and maintain a lower temperature under the same output power. Therefore, devices made on 100mm silicon carbide have lower requirements for heat dissipation design, contributing to the miniaturization of equipment.
3.3 Achieve high-frequency performance:
The saturated electron drift rate of silicon carbide is large and is twice that of silicon, which determines that silicon carbide devices can achieve higher operating frequencies and higher power density. Based on these excellent characteristics, the use limit performance of the 100mm silicon carbide substrate is better than that of the silicon substrate, which can meet the high application requirements under the conditions of high temperature, high voltage, high frequency, high power, etc., have already been applied to radio frequency devices and power devices.
4. FAQ of Silicon Carbide Substrate
Q1: We have received the silicon carbide wafers, but facing now a problem with cutting them. What we did is to cut parallel and vertical to the primary flat orientation with diamond wheel blade (diamond size 9 um) + cooling water. Unfortunately, after around 1 cm cutting, the blade would broken and the wafer cracked at the stopping point where blade got broken. I would be grateful if you can share some information with me about how you cut these wafers, or forward me to your technicians.
A1: For cutting silicon carbide substrate, here we suggest:
1/The SiC wafer material is hard and brittle. If we want to cut the edge, we use grinding to make the edge, but we don’t need to cut it. If it is cutting, it is also cut by diamond wire without diamond grinding wheel, and it is very slow. This cut is very easy to collapse. It’s better to cut it slowly with thread.
2/In this case, you can’t continue cutting. You need to take the SiC wafer down, separate the pieces, and then cut the pieces separately.
Q2: How thick is the final natural oxide layer of 4H silicon carbide wafer?
A2: There is no oxidation because 4H-SiC substrates are growing and packaging in the clean room.
For more information, please contact us email at [email protected] and [email protected].