Temperature of laboratory tubular PECVD electric furnace

The temperature range of the laboratory tubular PECVD electric furnace is wide, with common operating temperatures ranging from 200 ℃ to 450 ℃, and the highest temperature can reach 1200 ℃ or even higher (such as 1600 ℃), depending on the equipment model, deposition material, and process requirements. The following provides a detailed explanation from four aspects: temperature range, typical applications, temperature control technology, and temperature uniformity:

1. Temperature range
Low temperature range: The PECVD process allows for the adjustment of substrate temperature within the range of room temperature to 400 ℃, with common operating temperatures ranging from 200 ℃ to 450 ℃. For example, when depositing silicon nitride thin films, the substrate temperature should generally be between 300 ℃ and 450 ℃. Silicon nitride films deposited below 250 ℃ may have significant intrinsic stress, while films deposited above 450 ℃ are prone to cracking.
High temperature range: Some PECVD electric furnace coating systems can reach a maximum temperature of 1200 ℃, or even higher (such as 1600 ℃), which broadens the applicability of base materials and enables them to handle materials with higher melting points.

2. Typical application temperature
Polycrystalline silicon coating: The furnace tube temperature is usually set at 450 ℃, and the annealing stage temperature can be raised to 500-850 ℃.
Ammonia blowing stage: Temperature control at 400-450 ℃.
Pre sedimentation stage: The temperature is maintained at around 440 ℃.
Chemical reaction gas ionization stage: The temperature remains stable at 430-460 ℃.
Polycrystalline silicon annealing stage: The temperature range can reach 500-550 ℃.

3. Temperature control technology
PID control: using PID control and self-tuning adjustment technology to achieve temperature control accuracy of ± 1 ℃. For example, the continuous PE-CVD coating equipment is equipped with a LCD touch control system that supports 30 programmable temperature curve settings.
Multi zone PID control: For large-area substrates (such as 182mm/210mm silicon wafers or 1.6m × 1.8m photovoltaic glass), multi zone PID control technology is adopted to divide the furnace into multiple temperature zones (such as 6-zone heating plates), each zone is equipped with independent temperature sensors, real-time temperature data is collected and fed back to the temperature control module, and the heating power of the corresponding zone heating plate is quickly and accurately adjusted through adaptive PID algorithm.

4. Temperature uniformity
Importance: The temperature distribution inside the furnace should be uniform, otherwise it may cause uneven film thickness or composition, affecting the film performance. For example, in the photovoltaic industry, if the temperature difference within the silicon wafer surface is greater than 2 ℃, it will cause a deviation in film thickness of more than 5%, directly resulting in a loss of 0.2-0.5 percentage points in battery conversion efficiency.
Implementation method: By optimizing the furnace structure, adopting high-precision temperature control system, and dynamic compensation algorithm, etc., ensure uniform temperature distribution inside the furnace.