Quadrupole SIMS Analysis of Si Concentration in GaN Layers by a Molecular Ion Detection with a Minor Isotope

Abstract

The optimal condition suitable for using a quadrupole SIMS (Q-SIMS) instrument to measure the Si concentration in GaN layers for both selectively isotopic Si-implanted GaN and epitaxially Si-doped GaN was presented. The detection of ³⁰Si¹⁴N_- molecular ions under Cs⁺ primary ion bombardment realized the best dynamic range and the lowest detection limit for Q-SIMS analysis of Si in GaN layers. The detection limits of selectively isotopic ³⁰Si and the total amount of Si naturally occurring isotopes in GaN layers can reach 2 × 10¹⁴ cm^-3 and 8 × 10¹⁵ cm^-3, respectively. We concluded that a Q-SIMS instrument was applicable for the analysis of the Si depth distribution in GaN layers.