Vacuum coating CVD electric furnace

The vacuum coating CVD electric furnace is a key equipment for preparing thin films in a vacuum environment using chemical vapor deposition (CVD) technology. Its core advantages are reflected in high-purity deposition, precise composition control, excellent adhesion, wide material adaptability, and strong process stability. It is an indispensable high-end equipment in the fields of semiconductors, optics, aerospace, and so on.

1. Technical principles and core components
CVD electric furnace causes chemical reactions of gaseous precursors in a high-temperature vacuum environment, depositing solid thin films on the substrate surface. Its core system includes:
High temperature vacuum tube furnace: provides the high temperature environment required for the reaction (usually 800 ℃ -1700 ℃) and maintains a vacuum or specific atmosphere (such as inert gas, hydrogen).
Gas path system: Accurately control the flow rate and ratio of reaction gases (such as SiH ₄, NH ∝) and carrier gases (such as N ₂, Ar) to ensure the uniformity of film composition.
Vacuum system: Maintain the vacuum degree of the reaction chamber (as low as 10 ⁻⁵ Pa) through mechanical pumps, molecular pumps and other equipment to reduce impurity pollution.
Control system: adopting PID temperature control, multi-stage program temperature control and other technologies to achieve temperature accuracy within ± 1 ℃, ensuring process repeatability.

2. Analysis of Core Advantages
a. Preparation of high-purity thin films
Vacuum environment suppresses pollution: Under a vacuum of 10 ⁻² -10 ⁻⁵ Pa, the concentration of impurities such as oxygen and water vapor is extremely low, avoiding film oxidation or pollution.
Reduce gas molecule interference: Low pressure environment reduces the collision frequency of gas molecules, allowing the reaction gas to deposit more accurately on the substrate surface and improving the uniformity of the film.
b. Accurate control of film composition and structure
Dynamic adjustment of gas flow rate: By using a mass flow meter (MFC) to accurately control the proportion of reaction gas, gradient design or doping control of thin film composition can be achieved. For example, in silicon nitride thin films, the nitrogen content can be precisely controlled to optimize their insulation performance.
Temperature gradient control: Electric furnace zone temperature control technology (such as independent heating zone) can create temperature gradients, guide the direction of film growth, and prepare special structures such as columnar crystals and nanowires.
c. Excellent film adhesion
Substrate pretreatment function: The electric furnace can integrate plasma cleaning or ion bombardment modules to activate the substrate surface (such as removing oxide layers), enhance the chemical bonding between the film and the substrate, and improve adhesion.
In situ annealing treatment: After deposition, annealing is directly carried out in a vacuum environment to eliminate internal stress in the film and reduce the risk of cracking. For example, the hardness of diamond films can be improved after annealing.
d. Wide adaptability of materials
Support multiple deposition techniques: compatible with PECVD (plasma enhanced CVD), LPCVD (low-pressure CVD) and other variant technologies, capable of preparing thin films of refractory materials such as silicon carbide and gallium nitride.
Flexible substrate shape: suitable for flat, curved, or complex structural substrates (such as fiber optic coatings, aircraft engine blade coatings).
e. Process stability and repeatability
Closed loop control system: integrating pressure, temperature, and gas flow multi parameter feedback regulation to ensure process parameter fluctuations are less than 1%, suitable for large-scale industrial production.
Data traceability function: Record key parameters during the sedimentation process (such as temperature rise curve, gas flow rate changes) for quality control and process optimization.

3. Typical application scenarios
Semiconductor industry:
Crystalline silicon solar cells: Deposition of silicon nitride (SiN ₓ) anti reflection film improves light transmittance and cell conversion efficiency.
Integrated Circuit Manufacturing: Preparation of High-k gate dielectric layers (such as HfO ₂) to meet process requirements below 5nm.
In the field of optics:
Anti reflective film/reflective film: Deposition of magnesium fluoride (MgF ₂) or titanium dioxide (TiO ₂) thin film on the surface of optical lenses to improve light transmittance.
Laser crystal coating: Deposition of protective film for Nd: YAG laser crystal to extend its service life.
Aerospace:
Thermal barrier coating (TBC): Deposition of yttria stabilized zirconia (YSZ) coating on the surface of turbine blades, capable of withstanding high temperatures up to 1600 ℃ and extending component life.
Wear resistant coating: Deposition of diamond-like carbon (DLC) film to reduce the friction coefficient of aviation bearings.
medical apparatus and instruments:
Antibacterial coating: Deposition of silver (Ag) or copper (Cu) thin film on the surface of orthopedic implants to inhibit bacterial growth.
Bioactive coating: Deposition of hydroxyapatite (HA) film to promote bone cell adhesion (increase bone bonding strength).