3.1 Chemical Vapor Deposition (CVD)
CVD deposits thin films through chemical reactions of gas-phase precursors.
π Deposition Rate:
$$r = k_s P \exp\left(-\frac{E_a}{RT}\right)$$
π» Code Example 1: CVD Rate Modeling
# Requirements:
# - Python 3.9+
# - matplotlib>=3.7.0
# - numpy>=1.24.0, <2.0.0
import numpy as np
import matplotlib.pyplot as plt
def cvd_rate(T, P, Ea=150000):
"""CVD deposition rate"""
R = 8.314
rate = 1e6 * P * np.exp(-Ea/(R*(T+273)))
return rate
temps = np.linspace(400, 800, 100)
rates = [cvd_rate(T, 100) for T in temps]
plt.semilogy(temps, rates, 'b-', linewidth=2)
plt.xlabel('Temperature (Β°C)')
plt.ylabel('Deposition Rate (nm/min)')
plt.grid(True, alpha=0.3)
plt.show()3.2 Physical Vapor Deposition (PVD)
PVD includes sputtering and evaporation methods.
Summary
- CVD: chemical reactions in gas phase
- PVD: physical processes (sputtering, evaporation)
- Applications: semiconductors, optical coatings