Silicon carbide resistance long crystal furnace growing 6/8/12inch inch SiC ingot crystal PVT method

Short Description:

Silicon carbide resistance growth furnace (PVT method, physical vapor transfer method) is a key equipment for the growth of silicon carbide (SiC) single crystal by high temperature sublimation-recrystallization principle. The technology uses resistance heating (graphite heating body) to sublimate the SiC raw material at a high temperature of 2000~2500℃, and recrystallize in the low temperature region (seed crystal) to form a high-quality SiC single crystal (4H/6H-SiC). The PVT method is the mainstream process for the mass production of SiC substrates of 6 inches and below, which is widely used in the substrate preparation of power semiconductors (such as MOSFETs, SBD) and radio frequency devices (GaN-on-SiC).

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Working principle：

1. Raw material loading: high purity SiC powder (or block) placed at the bottom of the graphite crucible (high temperature zone).

2. Vacuum/inert environment: vacuum the furnace chamber (<10⁻³ mbar) or pass inert gas (Ar).

3. High temperature sublimation: resistance heating to 2000~2500℃, SiC decomposition into Si, Si₂C, SiC₂ and other gas phase components.

4. Gas phase transmission: the temperature gradient drives the diffusion of the gas phase material to the low temperature region (seed end).

5. Crystal growth: The gas phase recrystallizes on the surface of the Seed Crystal and grows in a directional direction along the C-axis or A-axis.

Key parameters:

1. Temperature gradient: 20~50℃/cm (control growth rate and defect density).

2. Pressure: 1~100mbar (low pressure to reduce impurity incorporation).

3.Growth rate: 0.1~1mm/h (affecting crystal quality and production efficiency).

Main features:

(1) Crystal quality
Low defect density: microtubule density <1 cm⁻², dislocation density 10³~10⁴ cm⁻² (through seed optimization and process control).

Polycrystalline type control: can grow 4H-SiC (mainstream), 6H-SiC, 4H-SiC proportion >90% (need to accurately control the temperature gradient and gas phase stoichiometric ratio).

(2) Equipment performance
High temperature stability: graphite heating body temperature >2500℃, furnace body adopts multi-layer insulation design (such as graphite felt + water-cooled jacket).

Uniformity control: Axial/radial temperature fluctuations of ±5 ° C ensure crystal diameter consistency (6-inch substrate thickness deviation <5%).

Degree of automation: Integrated PLC control system, real-time monitoring of temperature, pressure and growth rate.

(3) Technological advantages
High material utilization: raw material conversion rate >70% (better than CVD method).

Large size compatibility: 6-inch mass production has been achieved, 8-inch is in the development stage.

(4) Energy consumption and cost
The energy consumption of a single furnace is 300~800kW·h, accounting for 40%~60% of the production cost of SiC substrate.

The equipment investment is high (1.5M 3M per unit), but the unit substrate cost is lower than the CVD method.

Core applications:

1. Power electronics: SiC MOSFET substrate for electric vehicle inverter and photovoltaic inverter.

2. Rf devices: 5G base station GaN-on-SiC epitaxial substrate (mainly 4H-SiC).

3. Extreme environment devices: high temperature and high pressure sensors for aerospace and nuclear energy equipment.

Technical parameters：

Specification	Details
Dimensions (L × W × H)	2500 × 2400 × 3456 mm or customize
Crucible Diameter	900 mm
Ultimate Vacuum Pressure	6 × 10⁻⁴ Pa (after 1.5h of vacuum)
Leakage Rate	≤5 Pa/12h (bake-out)
Rotation Shaft Diameter	50 mm
Rotation Speed	0.5–5 rpm
Heating Method	Electric resistance heating
Maximum Furnace Temperature	2500°C
Heating Power	40 kW × 2 × 20 kW
Temperature Measurement	Dual-color infrared pyrometer
Temperature Range	900–3000°C
Temperature Accuracy	±1°C
Pressure Range	1–700 mbar
Pressure Control Accuracy	1–10 mbar: ±0.5% F.S; 10–100 mbar: ±0.5% F.S; 100–700 mbar: ±0.5% F.S
Operation Type	Bottom loading, manual/automatic safety options
Optional Features	Dual temperature measurement, multiple heating zones

XKH Services:

XKH provides the whole process service of SiC PVT furnace, including equipment customization (thermal field design, automatic control), process development (crystal shape control, defect optimization), technical training (operation and maintenance) and after-sales support (graphite parts replacement, thermal field calibration) to help customers achieve high-quality sic crystal mass production. We also provide process upgrade services to continuously improve crystal yield and growth efficiency, with a typical lead time of 3-6 months.