Determination of Trace Impurities in Electronic Grade Arsine by GC-ICP-QQQ

Importance of the Topic

Trace-level impurities in arsine are critical to control in the production of III–V semiconductors, where unwanted dopants such as germane, silane, phosphine, and hydrogen sulfide can impair device performance by introducing energy levels in the semiconductor bandgap.

Objectives and Article Overview

This study aims to develop a single-column, single-injection, multi-tune GC-ICP-QQQ method for simultaneous detection of multiple hydride impurities in electronic-grade arsine at sub-ppb levels, streamlining analysis and enhancing sensitivity.

Methodology

Standards of SiH4, PH3, GeH4, and H2S were prepared by dynamic dilution of a 10 ppm mix to 24 ppb; qualitative retention standards for H2Se, SbH3, and SnH4 were generated via hydride generation.
Cell gas modes (no gas, H2, O2) were optimized using MS/MS on an Agilent 8900 ICP-QQQ to remove spectral interferences, with O2 used for mass-shift measurements of P and S and H2 for on-mass Si detection.
A multi-tune time program automatically switches cell gas and acquisition parameters during the run, maximizing sensitivity for each analyte in one analysis.

Used Instrumentation

• Agilent 7890B GC with high-flow Deans switch to vent the arsine matrix
• Agilent 8900 Triple Quadrupole ICP-MS (ORS 4 cell, MS/MS capability)
• Column: Two 100 m × 0.53 mm × 5.0 µm DB-1; Agilent Select Low Sulfur column (CP8575) for SnH4
• UHP-MMSD dilution system (CONSCI) and 10 ppm custom gas standards

Main Results and Discussion

• Detection limits at 3× S/N: 0.51 ppb for SiH4, 0.01 ppb for GeH4, 0.02 ppb for PH3, 0.15 ppb for H2S using the multi-tune method.
• Single-gas O2 method also yields sub-ppb DLs with modest sensitivity loss.
• H2Se, SbH3, and SnH4 elute beyond arsine; DLs estimated at ≤ 1 ppb.

Benefits and Practical Applications

• Enables comprehensive impurity profiling in a single injection, reducing analysis time and sample consumption.
• Supports tighter quality control in semiconductor and optoelectronic manufacturing, improving device yield and performance.

Future Trends and Potential Applications

• Extension to additional hydrides (e.g., SeH4, SnH4) with specialized columns.
• Higher injection volumes or preconcentration for even lower detection limits.
• Integration of advanced ICP-QQQ technologies and automated monitoring for real-time gas analysis.

Conclusion

The developed GC-ICP-QQQ multi-tune method achieves sub-ppb detection of key hydride impurities in arsine using a single GC column and injection, offering robust, interference-free analysis and enhanced semiconductor process control.

References

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