Bulk AlN Manufacturing Flowsheet
High-temperature physical vapor transport crystal growth at 2,200°C, diamond multi-wire wafer slicing, double-sided CMP polishing, and atomic-scale AFM/HRXRD defect metrology.
Fab Sizing & High-Temperature PVT Parameters
UVC LED IQE (265nm)
72%
Internal quantum efficiency
Critical Breakdown Field
14.0 MV/cm
4× higher than SiC & GaN
Annual EBITDA
$4.34M
Operating earnings before D&A
20-Year Project IRR
17.2%
Discounted cash flow rate of return
UWBG Materials Physics & DUV Photonics
Ultra-Wide Bandgap (6.2 eV)PVT Sublimation Rate
207 µm/hr
Congruent vapor transport
Thermal Conductivity ($\kappa$)
315 W/m·K
Exceeds copper at 300K
UVC Wall-Plug Efficiency
20.7% (265nm)
7× higher than on sapphire (<3%)
Energy Bandgap ($E_g$)
6.2 eV (Cutoff: 200nm)
Deep UV optical transmission
Defect Suppression vs Sapphire
100,000× Lower Dislocation Density
Eliminates non-radiative traps
Power FOM Advantage
4× Higher than SiC / GaN
Baliga figure of merit ($E_{\text{crit}}^3$)
Underlying Scientific Equations
UVC Recombination Kinetics (ABC Model):
$$\text{IQE} = \frac{B n^2}{A_{\text{SRH}} n + B n^2 + C n^3}$$
Where Shockley-Read-Hall non-radiative recombination rate $A_{\text{SRH}} \propto \text{TDD}$. Lowering TDD below $10^4\,\text{cm}^{-2}$ boosts IQE to $>80\%$.
PVT Sublimation Flux:
$$J_{\text{Al}} = \frac{P_{\text{Al}} - P_{\text{Al,seed}}}{\sqrt{2\pi M_{\text{Al}} R T}}$$
Governed by Arrhenius sublimation kinetics ($2\text{AlN} \rightleftharpoons 2\text{Al}(g) + \text{N}_2(g)$) across the high-temperature crucible gradient.
20-Year Cleanroom Fab DCF & Cash Flow Analysis
10-Yr Straight Line D&A | 21% TaxGood Wafers Shipped
2,720 wafers/yr
Post-CMP boxed volume
Annual Revenue
$8.70M
Prime substrate sales
Annual Cash Opex
$4.36M
AlN source, TaC wear, labor, power
EBITDA Margin
49.9%
Specialty UWBG gross margin
Initial Fab Capex
$40.0M
2,300°C PVT furnaces, CMP, HRXRD
20-Year Project NPV
$13.82M
Discount rate: 10.0% WACC
Capex Payback Period
5.8 yrs
Breakeven on high-ASP volume
Unlevered Free Cash Flow
$3.12M / yr
Post-tax net operational cash flow
Bulk Aluminum Nitride & UWBG Mastery Quiz
Frequently Asked Questions
Bulk single-crystal Aluminum Nitride (AlN) provides true native, lattice-matched homoepitaxial substrates for high-aluminum-content AlGaN heterostructures. When UVC LEDs (265 nm) are grown on foreign sapphire substrates, the 13% lattice mismatch generates massive threading dislocation densities exceeding 10^9 to 10^10 cm^-2, causing severe non-radiative recombination that caps external quantum efficiency (EQE) below 3–5%. Native bulk AlN reduces dislocation density by 100,000x down to below 10^4 cm^-2, boosting internal quantum efficiency (IQE) to over 80%.
Because AlN decomposes before melting at atmospheric pressure, it cannot be pulled from a melt like silicon. It is synthesized by Physical Vapor Transport (PVT sublimation) in tungsten or tantalum carbide (TaC) crucibles under high-purity nitrogen (N2) at extreme temperatures of 2,100°C–2,300°C. Sintered AlN source powder at the bottom sublimates into Al vapor and N2 gas, which transport across a steep thermal gradient and recondense onto a cooler AlN seed crystal at growth rates of 100–350 µm/hr.
With an energy bandgap of 6.2 eV (nearly double that of 4H-SiC and GaN), AlN exhibits a critical electric breakdown field of 12–15 MV/cm. This is 4x higher than SiC and GaN, and 2x higher than beta-Ga2O3. According to Baliga's Figure of Merit, which scales with the cube of the breakdown field, AlN power devices can withstand 10kV to 20kV with drift layers that are 10x thinner, slashing specific on-resistance and switching losses for grid-scale solid-state transformers.
Pure single-crystal AlN boasts an exceptional thermal conductivity of ~320 W/m·K at room temperature—higher than copper and 20x higher than beta-Ga2O3 (~15 W/m·K). This enables high-power optical and electronic devices to dissipate concentrated heat fluxes exceeding 1,000 W/cm^2 directly through the native substrate, preventing thermal runaway and catastrophic thermal rollover.
Initial capex ($40M) is driven by ultra-high-temperature PVT sublimation furnaces with RF induction generators capable of stable 2,300°C operation, refractory TaC-coated hot zones, diamond multi-wire wafer slicers, and atomic-level CMP polishers. Key yield bottlenecks include thermal stress cracking during cool-down, residual oxygen impurity contamination that degrades thermal conductivity, and wafer bow/warp during 2-inch to 4-inch diameter expansion.