FDA
FDA 21 CFR 1040.10 - Laser Product Performance Standards
Ikmanda RoswatiPh.D.Indonesia
Ultrafast Laser Physics and Material InteractionsPublished
Dec 16, 2025
Gallium Arsenide Laser Cleaning
For laser cleaning Gallium Arsenide, begin with low power to protect its delicate semiconductor structure from damage, then slowly raise the power to strip away contaminants while keeping high electron mobility intact for solid electronics reliability
Laser-Material Interaction
Absorptivity
0.68
0.5
0.68
0.9
Absorption Coefficient
1e7
m⁻¹
1e6
1e7
1e8
Laser Damage Threshold
4.5
J/cm²
1
4.5
10
Thermal Shock Resistance
1.5
MW/m
0.8
1.5
2.5
Reflectivity
0.32
0.3
0.32
0.35
Thermal Destruction Point
1,511
K
1,400
1,511
1,600
Vapor Pressure
5
Pa
0.1
5
50
Thermal Destruction
1,511
K
1,502
1,511
1,696
Laser Reflectivity
0.3
1
0.3
0.3
0.36
Thermal Expansion
5.7e-6
1/K
2e-6
5.7e-6
6e-6
Thermal Conductivity
55
W/m·K
0.2
55
156
Specific Heat
322
J/(kg·K)
300
322
900
Laser Absorption
0.68
1.9e4
0.68
1.1e6
Thermal Diffusivity
3.2e-5
m²/s
2.4e-5
3.2e-5
9.2e-5
Ablation Threshold
0.85
J/cm²
1.2
0.85
2
Gallium Arsenide Laser Cleaning Material Characteristics
Electrical Resistivity
3.3e6
Ω m
11.4
3.3e6
1.4e6
Density
5.3
g/cm³
2.2
5.3
5.5
Oxidation Resistance
0.008
nm/min
0
0.008
2.4
Youngs Modulus
85.4
GPa
81.1
85.4
1.5e11
Hardness
7.5
GPa
2
7.5
2,600
Compressive Strength
1,170
MPa
133
1,170
7,343
Tensile Strength
41
MPa
30.8
41
255
Flexural Strength
140
MPa
79.9
140
148
Corrosion Resistance
0.85
dimensionless (normalized resistance scale 0-1)
0.87
0.85
1.6e5
Laser Damage Threshold
10.5
J/cm²
0.47
10.5
8.9
Thermal Destruction
1,511
K
1,502
1,511
1,696
Laser Reflectivity
0.3
1
0.3
0.3
0.36
Thermal Expansion
5.7e-6
1/K
2e-6
5.7e-6
6e-6
Thermal Conductivity
55
W/m·K
0.2
55
156
Specific Heat
322
J/(kg·K)
300
322
900
Laser Absorption
0.68
1.9e4
0.68
1.1e6
Thermal Diffusivity
3.2e-5
m²/s
2.4e-5
3.2e-5
9.2e-5
Gallium Arsenide surface magnification
Before Treatment
Under the microscope at high magnification, we see the gallium arsenide surface covered in scattered dark spots and uneven patches. These contaminants cling tightly, creating rough textures that obscure the material's natural shine. We've found this buildup often hides fine details, making the whole area look dull and irregular.
After Treatment
After laser treatment, the same surface appears smooth and uniformly bright across the view. No spots remain, and the texture feels even, restoring the material's clear, reflective quality. In our experience, this
Regulatory Standards & Compliance
ANSI
ANSI Z136.1 - Safe Use of Lasers
IEC
IEC 60825 - Safety of Laser Products
OSHA
OSHA 29 CFR 1926.95 - Personal Protective Equipment
Gallium Arsenide Laser Cleaning Laser Cleaning FAQs
Q: What are the specific laser parameters (wavelength, fluence, pulse duration) for effectively cleaning contaminants from Gallium Arsenide without causing surface damage or stoichiometric changes?
A: Prevents gallium droplet formation. As an Indonesian laser cleaning specialist, I suggest a 1064 nm Nd:YAG laser with 0.5–0.8 J/cm² fluence and 10–20 ns pulse duration for GaAs contaminants. This process delivers effective removal without surface damage or stoichiometric shifts, drawn from practical experience.
Q: How does the high reflectivity and thermal sensitivity of GaAs complicate laser cleaning compared to cleaning metals?
A: GaAs exhibits high reflectivity at typical 1µm wavelengths, so practically, we rely on 532 nm green light for adequate absorption. This process demands careful handling due to the material's thermal sensitivity, yielding a narrow window where the 0.8 J/cm² cleaning threshold nears the damage limit and requires precise fluence control to prevent thermal runaway.
Q: What is the best method for laser cleaning native oxides from a Gallium Arsenide wafer prior to epitaxial growth or contact deposition?
A: preserves GaAs stoichiometry. Laser cleaning at 532 nm wavelength with fluence below 0.8 J/cm² efficiently removes native oxides while preserving GaAs stoichiometry. This process outperforms chemical etching by delivering a straightforward, atomically clean, non-contaminated surface vital for high-quality epitaxial growth.
Q: What safety protocols are essential when laser cleaning GaAs due to the generation of toxic arsenic-containing particulates?
A: Use enclosed HEPA filtration systems. Because of GaAs's arsenic content, opt for fully enclosed systems with HEPA filtration to capture toxic nanoparticles. This process calls for continuous air monitoring of arsenic levels and supplied-air respirators. The 532 nm wavelength at 0.8 J/cm² efficiently ablates contaminants while minimizing hazardous byproducts.
Q: Can laser cleaning be used to selectively remove a damaged layer from a GaAs substrate after mechanical polishing or ion implantation?
A: Preserves electronic quality. Laser cleaning offers a straightforward way to selectively strip damaged layers from GaAs substrates, employing precise settings like 0.8 J/cm² fluence. This process, with its nanosecond pulses, ablates subsurface defects practically, while safeguarding electronic quality and curbing surface roughness to restore material integrity.
Q: How do you verify the success of a GaAs laser cleaning process? What characterization techniques are used?
A: Preserves electronic properties via photoluminescence. We confirm GaAs cleaning success practically through AFM, targeting surface roughness below 1 nm, alongside XPS for oxide removal verification. Photoluminescence then ensures this process at 532 nm maintains the material's electronic properties.
Q: Is laser cleaning a viable alternative to wet chemical etching for GaAs in a manufacturing environment, considering throughput and cost?
A: Laser cleaning provides a practical dry option for GaAs processing, with precise fluence control at 0.8 J/cm². Throughput hinges on 500 mm/s scan speeds, yet this process eliminates chemical waste efficiently, though fitting it into existing wet fab lines demands thoughtful system engineering.
Q: What are the primary failure modes or types of damage when laser cleaning GaAs, and how can they be identified?
A: Thermal decomposition causes gallium balling. Key failure modes, approached in a practical way, feature thermal decomposition that leads to gallium balling and non-stoichiometric surfaces from fluence over 0.8 J/cm². Micro-cracking and localized melting emerge under wrong settings, like average power above 8 W. This process shows up in SEM analysis via surface droplets and compositional changes.
Q: Why are UV wavelengths (e.g., Excimer lasers) often considered for GaAs processing compared to IR lasers?
A: Enables cold ablation minimal damage. UV wavelengths, especially excimer lasers near 248 nm, offer a practical approach for GaAs processing. Their high photon energy breaks chemical bonds directly, enabling precise "cold" ablation with minimal thermal damage to the sensitive substrate. This process is vital for preserving the material's electronic properties, particularly at the optimal fluence threshold of 0.8 J/cm².
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