High-temperature CVD tube furnace is a type of experimental or industrial equipment specifically designed for chemical vapor deposition (CVD) processes. It is widely used in high-tech fields such as new material synthesis, semiconductor manufacturing, nanomaterial preparation, carbon fiber processing, and phosphors. This equipment can perform thermal treatment and deposition reactions of materials under high temperature, vacuum, or controlled atmosphere conditions.

Core Structure and Components
Furnace: Typically features a double-layer stainless steel design with a built-in high-purity quartz or corundum tube (high-temperature resistance up to 1200-1600°C).

Heating System: Resistive heating (such as silicon carbide rods or silicon molybdenum rods) or infrared heating, combined with a PID temperature control system for precise temperature control (±1°C).

Gas System: A multi-channel mass flow meter (MFC) controls the flow of reactant gases (such as CH₄, SiH₄, NH₃, etc.) and carrier gases (Ar/N₂/H₂), and is equipped with an exhaust gas treatment device.

Vacuum System: Optional mechanical or molecular pumps are available to achieve a low vacuum environment (10⁻³ to 10⁻⁶ Torr).

Sample Holder: Quartz or graphite boat, supporting horizontal or vertical sample placement.

Typical Applications: Thin film deposition: Growth of SiC, GaN, graphene, carbon nanotubes, etc.

Doping Process: Phosphorus/boron diffusion of semiconductor materials.

Annealing: High-temperature crystallization of oxide thin films (such as ZnO and TiO₂).

Powder Synthesis: Preparation of high-purity ceramic powders (such as Al₂O₃ and ZrO₂).

Technical Advantages
Uniformity: Multi-temperature zone design ensures a temperature gradient within the furnace of ≤±5°C.

Controllability: Programmable heating profiles (such as step heating and constant temperature hold).

Safety: Overtemperature protection, gas leak alarm, and emergency cooling system.

Key Selection Parameters
Temperature Range: Commonly 800-1600°C, with ultra-high-temperature models exceeding 1800°C.

Tube Diameter: Φ50-200mm, affecting sample capacity and gas flow rate.

Compatible Atmospheres: Oxidizing (O₂), reducing (H₂), inert (Ar), or corrosive gases (special sealing design required).

Automation: Optional PLC control, remote monitoring, and data logging capabilities are available.

Operating Precautions
Pretreatment: A high-temperature oven is required for first use to remove impurities.

Gas Sequence: First, evacuate with inert gas, then introduce the reaction gas.

Maintenance: Clean the furnace tube regularly and inspect the seals for signs of wear.

Common Problems and Solutions: Uneven film: Check the gas distributor for blockage and optimize the carrier gas flow rate.

Temperature Fluctuation: Calibrate the thermocouple and check the heating element connections.

Contamination: Avoid sample volatile deposits and use high-purity gases.