Technology
Semiconductor Processing at the Atomic Scale
Applied Angstrom Technology pushes the boundaries of semiconductor etch technology. Our platform combines atomic layer etching, precision gas delivery, and advanced plasma sources to meet the demands of next-generation device architectures.
Core Capabilities
Six pillars of our atomic-scale etch technology platform
Self-Limiting Chemistry
Each ALE cycle consists of two half-reactions that saturate at exactly one atomic layer. This self-limitation is the fundamental mechanism that enables atomic-scale precision independent of feature geometry.
Thermal & Plasma Modes
Thermal ALE uses sequential gas-phase reactions for isotropic removal. Plasma ALE adds directional ion bombardment for anisotropic etching. Both modes achieve sub-nanometer etch per cycle control.
Cryogenic ALE
At -60 to -110°C, reactive gases physisorb in self-limiting monolayers. Combined with pulsed plasma, cryogenic ALE achieves <0.1% CD deviation in 3D NAND channel holes up to 10µm deep.
ARDE Elimination
Conventional RIE loses >98% of etchant flux at 100:1 aspect ratio. ALE converts flux-dependent etching to dose-dependent etching, making etch per cycle independent of feature depth.
Material Selectivity
Self-limiting surface chemistry enables selectivity >100:1 between adjacent materials. Critical for GAA nanosheet release (SiGe vs Si) and multilayer NAND structures.
Production Throughput
Hybrid ALE/RIE modes use ALE for critical atomic-layer steps and fast continuous etching for bulk removal. Pulsed plasma approaches achieve near-continuous throughput with ALE precision.
How Atomic Layer Etching Works
Surface Modification
A reactive gas (e.g., Cl₂ for silicon, HF for metal oxides) is introduced and reacts with only the top atomic layer of the surface. The reaction self-terminates once the surface is fully modified — no matter how long the exposure continues.
Purge
The chamber is purged with inert gas (Ar or N₂) to remove all unreacted modification species and volatile byproducts. This prevents uncontrolled etching and ensures clean separation between half-cycles.
Removal
The modified surface layer is removed by either low-energy ion bombardment (plasma ALE) or a second chemical reaction (thermal ALE via ligand exchange). Only the modified layer is removed — the underlying material is untouched.
Repeat
The cycle repeats. Each cycle removes exactly one atomic layer (typically 0.3-1.0 nm). The total etch depth equals the number of cycles multiplied by the etch per cycle — digital, deterministic control at the atomic scale.
Supported Materials
ALE chemistry is available for a wide range of semiconductor-relevant materials
| Material | ALE Mode | Chemistry | EPC (nm) |
|---|---|---|---|
| Silicon (Si) | Plasma | Cl₂ / Ar⁺ | 0.3-0.5 |
| SiO₂ | Plasma / Cryo | C₄F₈ / Ar⁺ | 0.3-0.8 |
| Si₃N₄ | Plasma | CHF₃ / Ar⁺ | 0.3-0.6 |
| HfO₂ | Thermal | HF / DMAC | 0.5-0.6 |
| Al₂O₃ | Thermal | HF / TMA | 0.6-1.0 |
| TiN | Plasma | Cl₂ / Ar⁺ | 0.3-0.5 |
| GaN | Plasma | Cl₂ / Ar⁺ | 0.3-0.4 |
| W | Plasma | O₂ / BCl₃ | 0.4-0.7 |
EPC = Etch Per Cycle. Actual values depend on process conditions.
Dive Deeper into ALE
Explore our comprehensive technical guide to atomic layer etching — mechanisms, materials, cryogenic ALE, and production applications.
ALE Technology Deep Dive