Selecting Process Materials for Epitaxy, Etch & Crystal Growth

Selecting Process Materials for Epitaxy, Etch & Crystal Growth

Semiconductor process materials must be matched precisely to the fab's process step and operating conditions. Semicera (Ningbo Miami Advanced Material Technology Co., LTD) is a manufacturer of high-purity semiconductor components including CVD SiC coating parts, TaC coating parts, PyC coating parts, SiC ceramics, quartz parts, and carbon fiber composites. This guide helps procurement and process engineers select the right material for epitaxy, etch, crystal growth, and diffusion processes.

[IMAGE: Cover | CVD-SiE-Etching-Ring.jpg | ALT: CVD SiC etching ring for plasma etch process | style="width:100%;"]

Problem Definition

Different semiconductor processes—epitaxy, annealing, etch, silicon carbide crystal growth—impose unique requirements on materials: ultra-high temperature (up to 2200°C), aggressive gases (NH₃, H₂, fluorine/chlorine plasma), high-vacuum, or thermal shock. Choosing the wrong material leads to contamination, particle generation, short service life, and yield loss.

Industry Background

The global semiconductor materials market reached $67.5 billion in 2024, a 3.8% increase from the prior year, according to SEMI. Wafer fabrication materials—including process chemicals and CVD materials—grew 3.3% to $42.9 billion. The semiconductor graphite market was valued at approximately $1.62 billion in 2024, and SiC‑coated graphite susceptors alone account for about $350 million globally. CVD SiC coating is the dominant protection method for graphite susceptors in MOCVD and epitaxial reactors.

Detailed Solution: Process‑Matched Materials

Semicera offers a portfolio of materials engineered for specific process steps. The selection is driven by working conditions (temperature, gas chemistry, mechanical load) and equipment type.

[IMAGE: Supporting | SiC-Wafer-Boat.jpg | ALT: SiC wafer boat for diffusion process | style="width:100%;"]

1. Epitaxy & RTP (Rapid Thermal Processing)

For MOCVD and epitaxial reactors operating at 1000–1600°C under continuous air supply or aggressive gas (NH₃/H₂) reduction, the recommended component is the CVD SiC coating graphite carrier (model CVD‑01). It features a typical coating thickness of 100 µm, purity 99.99995% (6N), and hardness 2500 Vickers. For ultra‑high temperature epitaxy up to 2200°C with extreme ammonia/hydrogen corrosion, the TaC coating graphite carrier (model CVD‑02) is preferred, with coating thickness 25–45 µm and outstanding chemical resistance.

2. SiC Crystal Growth

Silicon carbide crystal growth by PVT operates above 2000°C under ultra‑pure vacuum induction heating. Critical materials include semiconductor rigid felt (ash ≤20 ppm, thermal conductivity 0.15–0.35 W/m·K at 1500°C), soft felt (carbon content ≥99.99%), and CFC material (tensile strength 90–140 MPa, 3D needle‑punched matrix). For the raw charge, CVD SiC particulate (model CVD‑04) with 6N+ purity and grain size 1.0–5.0 mm is used.

3. Etch Process

Plasma etching chambers (ICP‑RIE, RIE) use fluorine/chlorine chemistries. The Etch ring (focus/edge ring) made from pure CVD solid SiC or high‑purity silicon single crystal provides plasma erosion rate below 2 nm/min and total metal purity below 5 ppb. Flatness tolerance is ≤10 µm.

[IMAGE: Proof | 5-Testing-center__Semicera.png | ALT: Quality inspection lab at Semicera | style="width:100%;"]

4. Oxidation/Diffusion (LPCVD, Furnace)

Horizontal/vertical diffusion furnaces require SiC wafer boats (model SiC‑01) that survive up to 1600°C with zero deformation and >5× longer life than quartz. SiC furnace tubes (model SiC‑02) are gas‑tight up to 3000 mm length. SiC paddles (model SiC‑03) handle cantilever loads up to 15 kg at >1100°C. For lower‑temperature processes, quartz furnace tubes (OH <20 ppm) and quartz wafer boats (slot pitch tolerance ±0.05 mm) are cost‑effective alternatives.

Step‑by‑Step Material Selection

1. Identify the process step (epitaxy, etch, crystal growth, diffusion).
2. Define operating conditions: temperature range, gas species, vacuum/pressure, mechanical stress.
3. Match material properties: purity, coating type, thermal conductivity, CTE, erosion resistance.
4. Select product form: solid SiC, SiC‑coated graphite, TaC‑coated graphite, quartz, CFC, felt.
5. Verify supplier capabilities: Semicera’s 100+ engineers, 40,000 m² facility, and 100% quality testing ensure compliance.

Use Cases

• North America Fab (epitaxy): 900 units/month of SiC wafer boats (SiC‑01) reduced equipment maintenance downtime by 15% over 2 years.
• Asia‑Pacific Fab (epitaxy): 200 units/month of SiC furnace tubes improved wafer yield by 2.5% with ultra‑low particle counts.
• Korea Fab (etch): 500 pcs/month of CVD SiC coating graphite carriers (CVD‑01) cut edge ring replacement frequency by 20%.
• Taiwan Crystal Grower: 1000 units/year of CFC material provided significant energy efficiency and temperature uniformity in silicon single‑crystal furnaces.

Material Comparison Table

Property	CVD SiC Coating (CVD‑01)	TaC Coating (CVD‑02)	CVD Solid SiC (Etch Ring)	CFC Material
Max Operating Temp	1600°C	2200°C	1600°C	>2000°C
Purity / Ash	≤5 ppm	–	Metal <5 ppb	≤10 ppm
Key Resistance	Thermal shock	NH₃/H₂ etching	F/Cl plasma	Thermal shock
Typical Thickness	100 µm	25–45 µm	Bulk solid	3D weave

[IMAGE: CTA | 10-Graphite-machining-machine_Semicera.png | ALT: Graphite machining at Semicera – request a quote | style="width:100%;"]

Frequently Asked Questions

Conclusion

Selecting semiconductor process materials based on exact process conditions—temperature, chemistry, mechanical stress—maximizes uptime, yield, and component lifespan. Semicera’s vertically integrated manufacturing (40,000 m² facility, 600+ employees, 100+ R&D engineers) delivers products from high‑purity graphite to advanced TaC coatings, backed by proven field results. Evaluate your process step and contact Semicera for a material recommendation tailored to your equipment.