High‐sensitivity analysis of impurities in gaas using multi‐element‐doped gaas standard samples

Abstract

AbstractIn order to improve the quality of GaAs crystal, it is indispensable to conduct ultramicroanalysis of impurities in GaAs. For the analyses in this paper standard samples were made by adding a certain amount of impurities which can adequately be detected by chemical analyses. Using these samples, the SSMS, SIMS and chemical analysis methods are examined. The results are: (1) three chemical analysis methods (FLAA, ICP and colorimetric methods) are examined and permit a detection limit of 0.05 ∼ 5 ppm and a CV value of ±30%. (2) For the SSMS method, a process for making a specimen electrically conductive by applying a vacuum‐evaporated silver film is introduced. Comparing this result with those obtained by the chemical methods, a relative sensitivity factor is found which permits determination of the absolute value and it is possible to conduct analysis with detection limits of 10 ∼ 30 ppb and CV value of ±30%. (3) For the SIMS method, the secondary ionization yields for B, Al, Si, S, Cr and Mn are obtained, by comparison with the results of chemical analysis, which makes absolute quantitative analyses of these elements possible. The accuracy of quantitative analysis in which ion‐implanted specimens were used for the standard samples is confirmed.