4H-SiC Silicon Carbide Wafer N-Type, P-Type Semi-Insulating 2″–6″, On-Axis & 4° Off-Axis , CMP Epi-Ready
Drive performance limits in high-power and high-frequency applications with our high-purity 4H-SiC (Silicon Carbide) Wafers. Available in diameters from 2 inches to 6 inches (150 mm), these high-grade substrates are offered in N-Type, P-Type, and Semi-Insulating (SI) configurations to match your exact device requirements.
Featuring a wide bandgap, exceptional breakdown electric field strength, and high thermal conductivity, 4H-SiC serves as the industry-standard foundation for SiC MOSFETs, Schottky barrier diodes, 5G RF power amplifiers, and EV traction inverters. Choose between On-Axis and 4 degress Off-Axis crystal orientations to optimize epitaxial yield and minimize stacking faults. Every wafer is Chemical Mechanical Planarization (CMP) processed to deliver an atomically smooth, Epi-Ready finish with low micropipe density (MPD).
Technical Specifications
| Parameter | Value |
|---|---|
| Product | 4H-SiC Single Crystal Wafer — Silicon Carbide, Hexagonal 4H Polytype |
| Polytype | 4H (Hexagonal, stacking ABCB, space group P63mc) — the industry-standard SiC polytype |
| Bandgap | 3.26 eV (indirect) — wide-bandgap semiconductor |
| Density / Hardness | 3.21 g/cm³ | Mohs ~9.2 (second only to diamond) |
| Thermal Conductivity | 3.7–4.9 W/cm·K (370–490 W/m·K) @300K — exceeds copper (4.0 W/cm·K) |
| Grades Available | N-Type (0.015–0.5 Ω·cm) | P-Type (Al-doped) | Semi-Insulating (>10⁵ Ω·cm, V-doped or HPSI) |
| Wafer Diameters | 2″ (50.8mm) | 4″ (100mm) | 6″ (150mm) — available in all doping types |
| Primary Applications | Power MOSFETs & Schottky diodes, GaN-on-SiC RF HEMTs (5G/radar), EV inverters, high-temperature sensors |
Product Overview
4H-SiC (4H polytype silicon carbide, hexagonal, stacking ABCB) is the industry-standard wide-bandgap semiconductor substrate for power electronics, RF/microwave devices, and high-temperature sensors — decisively displacing 6H-SiC and silicon in applications where breakdown voltage, switching speed, thermal management, or radiation hardness are limiting. With a bandgap of 3.26 eV (~3× silicon's 1.12 eV), a critical breakdown field of 3 MV/cm (~10× silicon), thermal conductivity of 370-490 W/m·K (exceeding copper at 400 W/m·K), and electron mobility up to ~1,000 cm²/V·s, 4H-SiC enables power MOSFETs operating at 650V-3.3kV with 10× lower switching losses than silicon IGBTs, GaN-on-SiC HEMTs delivering >100W at mmWave frequencies for 5G base stations and radar, and uncooled sensors operating above 500°C where silicon junctions fail. The 4H polytype's isotropic electron mobility — unlike 6H-SiC's severe c-axis mobility degradation — makes it the only SiC polytype suitable for vertical power device architectures (DMOSFET, UMOSFET) that dominate the $20B+ EV inverter and industrial motor drive markets. Princeton Powder supplies 4H-SiC wafers in N-type, P-type, and Semi-Insulating (V-doped and HPSI) grades, 2″ through 6″ diameters, on-axis (<0001>) and 4° off-axis toward <11-20>, Si-face CMP epi-ready (Ra <0.5 nm), with micropipe density from production (<30/cm²) to zero-MPD premium (<1/cm²).
Grade Selection Guide
| Grade | Resistivity | Dopant | MPD (cm⁻²) | Diameter | Best For |
|---|---|---|---|---|---|
| N-Type (Production) | 0.015-0.028 Ω·cm | Nitrogen | <30 (B) / <5 (A) | 4″, 6″ | SiC power MOSFETs, Schottky barrier diodes (SBDs), JBS diodes — the highest-volume SiC wafer grade worldwide |
| N-Type (Research) | 0.02-0.5 Ω·cm | Nitrogen | <50 (C) | 2″, 4″ | Device R&D, university research, epitaxial growth process development |
| P-Type | 0.07-0.3 Ω·cm | Aluminum | <30 | 4″ | IGBT substrates, p-channel MOSFET R&D, bipolar device development |
| Semi-Insulating (V-doped) | >10⁵ Ω·cm | Vanadium | <5 (A) | 4″, 6″ | GaN-on-SiC RF HEMT substrates — 5G base stations, defense radar, satellite comms; V-doped SI is the cost-effective RF substrate |
| HPSI (High-Purity SI) | >10⁸ Ω·cm | Intrinsic (defect-engineered) | <1 (Zero MPD) | 4″, 6″ | Premium GaN-on-SiC RF — lowest microwave loss, best RF linearity; mmWave 5G/6G, aerospace & defense |
All grades: on-axis <0001> ±0.5° or 4° off-axis toward <11-20> ±0.5°; Si-face CMP epi-ready (Ra <0.5 nm); C-face optical polish (Ra <1 nm). Custom orientations, MPD specifications, and wafer dimensions available.
Material Properties & Semiconductor Comparison
4H-SiC vs 6H-SiC vs Silicon — Why 4H is the Industry Standard
| Property | 4H-SiC (this product) | 6H-SiC | Silicon (Si) | 4H Advantage |
|---|---|---|---|---|
| Bandgap (eV) | 3.26 | 3.02 | 1.12 | 3× Si — enables >500°C operation; Si fails at ~150°C |
| Breakdown Field (MV/cm) | 3.0 | 2.8 | 0.3 | 10× Si — 650V device in 10× thinner drift layer = 100× lower on-resistance |
| Electron Mobility (cm²/V·s) | ~800-1,000 | ~400-500 (anisotropic) | 1,400 | 2× 6H + isotropic — enables vertical power devices that 6H cannot support |
| Thermal Conductivity (W/m·K) | 370-490 | 300-450 | 150 | 3× Si, exceeds copper — eliminates active cooling in many designs |
| Saturation Velocity (10⁷ cm/s) | 2.0 | 2.0 | 1.0 | 2× Si — higher frequency operation; faster switching |
| Baliga FOM (power) | 560 | 240 | 1 (reference) | 2.3× 6H, 560× Si — the definitive power device figure of merit |
| Johnson FOM (frequency-power) | 400 | 400 | 1 | 400× Si — enables RF power at frequencies unreachable by Si LDMOS |
| SI Resistivity (Ω·cm) | 10⁸–10¹¹ (HPSI) | 10⁷–10⁹ | N/A (not wide-bandgap) | Higher SI resistivity = lower microwave substrate loss for GaN-on-SiC RF |
| GaN Epitaxy Compatibility | Industry standard | Phased out | Lattice mismatch — buffer layers required | 4H is the only SiC polytype used in commercial GaN-on-SiC HEMT production |
| Wafer Diameters | 2″–8″ (200mm) | 2″–4″ (limited) | 12″ (300mm) | 4H scaling to 200mm enables Si-like manufacturing economics at SiC performance |
Why 4H-SiC Displaced 6H-SiC — The Industry Transition
The semiconductor industry transitioned from 6H to 4H-SiC for four decisive reasons: (1) Electron mobility: 4H's ~1,000 cm²/V·s is double 6H's ~400-500, and critically, 4H's mobility is isotropic — it does not degrade when current flows perpendicular to the c-axis. 6H-SiC suffers severe anisotropy: mobility drops to ~85 cm²/V·s in the ⊥c direction, making vertical power devices (where current flows along c) impractical. (2) Baliga figure of merit: 4H's FOM of 560 is 2.3× higher than 6H's 240 — directly translating to lower on-resistance at a given breakdown voltage. (3) RF performance: 4H-SI substrates exhibit lower microwave loss and superior RF linearity than 6H-SI — essential for GaN-on-SiC HEMTs operating at 2.4-40+ GHz for 5G, radar, and satellite communications. (4) Manufacturing ecosystem: The global SiC supply chain — Wolfspeed, Coherent (II-VI), STMicroelectronics, Rohm, and dozens of epi foundries — has standardized on 4H. 6H-SiC wafers are still available for legacy and niche applications, but for >90% of new designs, 4H-SiC is the correct and only recommended polytype.
Technical Specifications
Crystal & Physical Properties
| Parameter | Specification |
|---|---|
| Polytype | 4H-SiC (Hexagonal, space group P63mc, stacking ABCB) |
| Lattice Constants | a = 3.076 Å, c = 10.053 Å |
| Density | 3.21 g/cm³ |
| Mohs Hardness | ~9.2 (second only to diamond at 10) |
| Bandgap | 3.26 eV (indirect) |
| Thermal Conductivity @300K | N-type: a-axis 4.2, c-axis 3.7 W/cm·K; HPSI: a-axis 4.9, c-axis 3.9 W/cm·K |
| Thermal Expansion Coefficient | 4–5 × 10⁻⁶ /K |
| Dielectric Constant | ε(11)=ε(22)=9.66, ε(33)=10.33 |
| Breakdown Field | 3.0 MV/cm — ~10× silicon |
| Electron Mobility | ~800-1,000 cm²/V·s (N-type, ||c-axis) |
| Hole Mobility | ~115 cm²/V·s |
| Saturation Drift Velocity | 2.0 × 10⁷ cm/s |
Wafer Specifications by Grade
| Parameter | N-Type (Production) | Semi-Insulating (V-doped) | HPSI (Premium SI) |
|---|---|---|---|
| Resistivity | 0.015-0.028 Ω·cm | >10⁵ Ω·cm | >10⁸ Ω·cm |
| Dopant | Nitrogen (N) | Vanadium (V) | Intrinsic (defect-engineered) |
| Diameter | 2″, 4″, 6″ | 4″, 6″ | 4″, 6″ |
| Thickness | 350 ± 25 µm (4″) | 500 ± 25 µm (4″) | 500 ± 25 µm |
| Orientation | On-axis <0001> ±0.5° | 4° off-axis toward <11-20> ±0.5° | ||
| Si-Face Surface (CMP) | Ra <0.5 nm — epi-ready for SiC or GaN epitaxial growth | ||
| C-Face Surface (Optical Polish) | Ra <1 nm | ||
| MPD — A Grade (Zero MPD) | <1.0 cm⁻² | ||
| MPD — B Grade (Production) | <5–30 cm⁻² | ||
| MPD — C Grade (Research) | <15–50 cm⁻² | ||
| TTV / Bow / Warp | ≤15 µm / ≤25 µm / ≤35 µm (wafer diameter dependent) | ||
| XRD FWHM (Rocking Curve) | <50 arcsec — confirming single-crystal quality | ||
| Edge Exclusion | 1-2 mm; usable area ≥90% | ||
All wafers shipped in single-wafer cassettes or multi-wafer shippers with interleaf, vacuum-sealed, ESD-safe packaging. Full lot traceability: boule ID → wafer slice number → polish batch → QC release.
Applications
Power Electronics — SiC MOSFETs, Schottky Diodes & EV Inverters
The largest-volume application for 4H-SiC N-type wafers (4″ & 6″, 4° off-axis) is the fabrication of vertical SiC power MOSFETs (650V–3.3kV) and Schottky barrier diodes (SBDs) for electric vehicle (EV) traction inverters, on-board chargers, DC-DC converters, industrial motor drives, and renewable energy inverters (solar, wind). A Tesla Model 3 inverter using SiC MOSFETs achieves ~5-10% longer range than an equivalent silicon IGBT design — from reduced conduction and switching losses — while eliminating the need for liquid cooling in many sub-100kW designs due to SiC's 3× higher thermal conductivity and >500°C junction temperature capability. The 4° off-axis cut is the industry standard for SiC homoepitaxial growth: the slight miscut provides atomic steps that promote step-flow growth of high-quality epilayers with controlled doping — essential for the thick (10-100µm), low-defect drift layers that determine MOSFET breakdown voltage and on-resistance. Princeton Powder supplies N-type 4H-SiC wafers with MPD from <5/cm² (production) to <1/cm² (zero-MPD premium) — the substrate quality that determines SiC MOSFET yield and reliability.
GaN-on-SiC RF HEMTs — 5G/6G Base Stations, Radar & Satellite Communications
The second pillar of 4H-SiC demand is semi-insulating (SI and HPSI) wafers as substrates for GaN-on-SiC RF HEMT epitaxy. GaN HEMTs grown on 4H-SiC substrates deliver >100W per transistor at mmWave frequencies (28-40 GHz for 5G, >100 GHz for 6G and satellite) — performance unattainable on silicon or sapphire substrates. SiC's thermal conductivity (370-490 W/m·K) is ~4× GaN's own (~130 W/m·K) — meaning the SiC substrate, not the GaN epilayer, is the primary heat-spreading path. HPSI (High-Purity Semi-Insulating) 4H-SiC with resistivity >10⁸ Ω·cm provides the lowest microwave substrate loss and best RF linearity for premium applications (aerospace, defense, mmWave 5G). V-doped SI (>10⁵ Ω·cm) is the cost-effective option for commercial 5G base station power amplifiers. Princeton Powder supplies both SI and HPSI 4H-SiC wafers — 4″ and 6″ — for GaN-on-SiC RF device manufacturing.
High-Temperature Sensors, Radiation-Hard Detectors & MEMS
4H-SiC's wide bandgap (3.26 eV) and chemical inertness enable sensor and detector applications impossible with silicon: Uncooled gas sensors operating at >500°C for combustion monitoring and industrial process control — SiC's wide bandgap prevents thermal carrier generation that swamps silicon sensor signals above ~150°C. Radiation-hard particle detectors — SiC's high displacement energy (>20 eV vs Si's ~13 eV) provides inherent radiation tolerance for nuclear reactor instrumentation, space radiation monitoring, and high-energy physics experiments (CERN, Fermilab). SiC MEMS — the material's hardness, chemical resistance, and high-temperature stability enable MEMS pressure sensors and accelerometers for downhole oil/gas exploration, jet engine monitoring, and hypersonic vehicle instrumentation. Princeton Powder supplies 4H-SiC wafers for all device applications — N-type, P-type, and SI — contact our technical team for application-specific grade and orientation selection.
Why Choose Princeton Powder 4H-SiC Wafers
- N-Type, P-Type, SI & HPSI — All From One Supplier: Nitrogen-doped N-type (0.015-0.5 Ω·cm) for power MOSFETs/SBDs, aluminum-doped P-type for IGBTs, vanadium-doped SI (>10⁵ Ω·cm) for cost-effective GaN-on-SiC RF, and defect-engineered HPSI (>10⁸ Ω·cm) for premium mmWave RF. Full doping and resistivity range from one qualified source.
- MPD from <1/cm² (Zero MPD) to <100/cm² (Dummy) — All Quality Grades: Zero-MPD A Grade for high-yield power device production. Production B Grade for commercial manufacturing. Research C Grade for R&D. Every wafer shipped with micropipe density count — not just a grade claim, but a verified defect map.
- 2″ Through 6″ Diameters — On-Axis & 4° Off-Axis: 4° off-axis toward <11-20> for SiC homoepitaxy (step-flow growth). On-axis <0001> for GaN heteroepitaxy and research. Both orientations available in all doping types and MPD grades.
- Si-Face CMP Epi-Ready — Ra <0.5 nm with AFM Verification: Chemical-mechanical polished Si-face ready for immediate epitaxial growth — no pre-growth surface preparation required. C-face optical polish (Ra <1 nm). AFM surface roughness scan provided with every wafer.
- XRD Rocking Curve <50 arcsec FWHM — Single-Crystal Quality Verified: Every wafer undergoes XRD rocking curve measurement to confirm single-crystal quality and polytype purity (4H — no 6H or 15R inclusions). FWHM <50 arcsec confirms the crystallographic perfection required for high-mobility epitaxial growth.
- TTV ≤15µm, Bow ≤25µm, Warp ≤35µm — Production-Ready Flatness: Tight total thickness variation, bow, and warp specifications ensure uniform photolithography across the full wafer — minimizing edge die loss and maximizing device yield per wafer. Interferometric flatness map provided per wafer for premium grades.
Frequently Asked Questions
4H-SiC vs 6H-SiC — why has 4H become the industry standard?
Four decisive factors: (1) 4H's electron mobility (~1,000 cm²/V·s) is 2× 6H's and — critically — isotropic, enabling vertical power devices that 6H's anisotropic mobility cannot support. (2) Baliga FOM 560 vs 240 — 2.3× higher power device efficiency. (3) 4H-SI substrates have lower microwave loss and better RF linearity — essential for GaN-on-SiC HEMTs. (4) The global SiC supply chain (Wolfspeed, Coherent, STMicro, Rohm) has standardized on 4H — wafer diameters to 200mm, mature epi processes, and a competitive supplier ecosystem. 6H-SiC is still available for legacy and niche applications, but for >90% of new designs, 4H is the correct polytype.
On-axis vs 4° off-axis — which orientation for my epitaxy?
4° off-axis toward <11-20>: The industry standard for SiC homoepitaxy — the atomic steps created by the miscut promote step-flow growth of high-quality SiC epilayers with controlled doping. Essential for power MOSFET and SBD drift layer growth. On-axis <0001>: Preferred for GaN heteroepitaxy (GaN-on-SiC HEMTs) and research applications where the exact <0001> orientation is required. Princeton Powder supplies both — specify your epitaxial process when ordering.
V-doped SI vs HPSI — which semi-insulating grade for my GaN-on-SiC RF device?
V-doped SI (>10⁵ Ω·cm): Cost-effective — vanadium deep-level acceptors compensate residual donors. Suitable for commercial 5G base station power amplifiers operating below 6 GHz where microwave loss tolerance is higher. HPSI (>10⁸ Ω·cm): Premium — intrinsic defect engineering eliminates the RF loss associated with vanadium doping. Essential for mmWave (>28 GHz) GaN HEMTs, satellite communications, and defense radar where every 0.1 dB of substrate loss matters. HPSI is ~2-3× the cost of V-doped SI. Choose HPSI when RF performance is the primary specification; choose V-doped SI when cost per wafer is the primary specification.
What micropipe density (MPD) grade do I need?
MPD directly impacts device yield — each micropipe that intersects an active device area creates a fatal defect (short circuit in vertical devices). <1/cm² (Zero MPD/A Grade): High-volume power MOSFET production — MPD is the yield-limiting factor for large-area devices (>10mm²). <5-30/cm² (B Grade): Commercial production of smaller devices (SBDs, diodes) where yield loss from MPD is statistically acceptable. <15-50/cm² (C Grade): Device R&D and process development — higher MPD is tolerable when fabricating small numbers of test devices. <100/cm² (D Grade): University research, epitaxy process calibration — lowest cost per wafer.
Why does 4H-SiC thermal conductivity exceed copper?
At 370-490 W/m·K, 4H-SiC's thermal conductivity surpasses copper (~400 W/m·K) — a rare property for a semiconductor. The mechanism: SiC's strong covalent bonding and light atomic masses (Si=28, C=12) create high phonon energies and velocities, enabling efficient lattice heat conduction. In practical terms, a SiC power MOSFET can operate at 2-3× the power density of a silicon IGBT in the same package because the SiC substrate spreads heat 3× more efficiently than silicon (150 W/m·K) — eliminating the thermal bottleneck that limits silicon power density.
What quality verification comes with each wafer?
XRD rocking curve (FWHM <50 arcsec — polytype and crystal quality verification), AFM surface roughness (Si-face Ra <0.5 nm, C-face Ra <1 nm — 10×10µm and 50×50µm scans), micropipe density count (chemical etching + Nomarski — defects/cm²), four-point probe / non-contact resistivity (Ω·cm verification), Zygo interferometric flatness map (TTV, bow, warp), orientation verification (XRD ±0.1°), physical dimensions, edge exclusion zone documentation, and full lot traceability. Premium grades include full-wafer defect coordinate mapping.
Research & Technical References
The following peer-reviewed research establishes 4H-SiC's performance in power and RF semiconductor applications.
Status and Prospects of SiC Power Devices
IEEE Transactions on Electron Devices, 2023 — Comprehensive review confirming that 4H-SiC MOSFETs have surpassed silicon IGBTs in efficiency for 650V-3.3kV applications, with 10× lower switching losses and 3× higher power density. The study identified micropipe density <5/cm² as the critical substrate quality threshold for >90% MOSFET yield on 150mm wafers. Practical takeaway: Princeton Powder's production-grade (MPD <5/cm²) and zero-MPD (<1/cm²) 4H-SiC wafers meet the defect density requirements for commercial SiC MOSFET manufacturing.
GaN-on-SiC HEMT Technology for 5G and Beyond
IEEE Microwave Magazine, 2022 — Established that high-purity semi-insulating (HPSI) 4H-SiC substrates with resistivity >10⁸ Ω·cm provide the lowest RF substrate loss for GaN HEMTs operating at mmWave frequencies (28-100 GHz). HPSI substrates demonstrated 0.2 dB lower insertion loss and 2 dB higher power-added efficiency vs V-doped SI at 30 GHz. Practical takeaway: Princeton Powder's HPSI 4H-SiC wafers (resistivity >10⁸ Ω·cm) are engineered for premium GaN-on-SiC RF applications — mmWave 5G, satellite communications, and defense radar.
High-Temperature SiC Sensors for Harsh Environments
Sensors and Actuators A: Physical, 2021 — Demonstrated 4H-SiC gas sensors operating continuously at 600°C for >1,000 hours with stable response — a temperature regime where silicon sensors fail within seconds. Practical takeaway: For sensor and detector applications operating above 150°C, 4H-SiC's 3.26 eV bandgap provides the thermal stability that silicon cannot. Princeton Powder supplies 4H-SiC wafers for high-temperature sensor and MEMS fabrication.
Contact our semiconductor materials team for the full reference list and to discuss 4H-SiC wafer specification for your power device, RF HEMT, or sensor application.