Surface Reaction Kinetics Simulator

Comprehensive modeling of ion-enhanced etching mechanisms, radical adsorption, passivation layer dynamics, and temperature-dependent surface chemistry. Simulate Langmuir-Hinshelwood kinetics, etch yield functions, and the critical balance between etching and polymer deposition.

Key Physics

Surface reactions control etch rate and selectivity through complex interplay of ion bombardment, radical adsorption, and temperature. Ion-enhanced etching synergistically combines chemical and physical processes while passivation layers protect sidewalls to achieve anisotropy.

Running
1.0×

Surface Reaction Parameters

Etch Rate

245
nm/min

Etch Yield

0.85
atoms/ion

Surface Coverage (θ)

0.62
ML

Polymer Thickness

3.2
nm

Chemical Component

125
nm/min

Physical Component

120
nm/min

Deposition Rate

45
nm/min

3D Surface Reaction Dynamics

Theoretical Background

Langmuir-Hinshelwood Adsorption

Surface coverage of reactive species follows Langmuir isotherm:

θ = (k_ads · Γ_radical · τ_residence) / (1 + k_ads · Γ_radical · τ_residence) where τ_residence = τ₀ · exp(E_des / k_B T)

Ion-Enhanced Etching Mechanism

Combined ion and radical etch rate (synergistic model):

R_etch = R_chem + R_phys + R_synergy R_synergy = k_syn · Γ_ion^α · Γ_radical^β · θ Typical exponents: α ≈ 0.5, β ≈ 1.0

Etch Yield Function

Energy-dependent etch yield (atoms removed per incident ion):

Y(E) = Y_max · θ · (1 - E_th/E)^n for E > E_th = 0 for E ≤ E_th Y_max depends on coverage: Y_max = Y₀ · (1 + K·θ)

Arrhenius Temperature Dependence

Chemical etch rate follows Arrhenius law:

R_chem(T) = A · exp(-E_a / k_B T) · Γ_radical · θ Typical E_a: 0.2-0.5 eV for fluorine-based etching

Passivation Layer Formation

Polymer deposition from CFₓ precursors competes with etching:

dh_polymer/dt = Γ_polymer · s_polymer · V_monomer - R_sputter where R_sputter = Y_poly · Γ_ion · (E_ion / E_th_poly)

Surface Site Balance

Dynamic surface coverage (ML = monolayer):

dθ/dt = Γ_radical · s · (1 - θ) - k_des · θ - Y · Γ_ion · θ Steady-state: θ_ss = (Γ_radical · s) / (Γ_radical · s + k_des + Y · Γ_ion)

Reaction Probability

Temperature and coverage-dependent sticking coefficient:

s(T, θ) = s₀ · (1 - θ)^m · exp(-E_barrier / k_B T) Precursor model: m = 0 (Langmuir), m = 1 (dissociative)

Etch vs Deposition Transition

Critical ratio determining etch/deposit regime:

R_net = R_etch - R_deposit Transition: R_etch = R_deposit when Γ_ion/Γ_polymer = K_crit(E_ion)