Repeatability of Si concentration measurements in Si-doped GaN films

• Published in: Journal of vacuum science & technology. A, Vacuum, surfaces, and films Vol. 15; no. 5; pp. 2565 - 2568
• Main Authors: Chi, P. H., Simons, D. S., Wickenden, A. E., Koleske, D. D.
• Format: Journal Article
• Language: English
• Published: 01-09-1997
• Subjects: GaN
• ISSN: 0734-2101; 1520-8559
• DOI: 10.1116/1.580772

In high mass resolution secondary ion mass spectrometry
Cs
+
depth profile measurements of Si in GaN films, the secondary ion intensity ratio of
28
Si
−
to the matrix
69
Ga
−
signal has been observed to be poorly repeatable from measurement to measurement. In some cases the
69
Ga
−
signals from adjacent areas showed different intensity levels even though the
28
Si
−
intensities were similar. Variation of the
69
Ga
−
matrix signal from run to run creates a large uncertainty in the determination of the Si concentration in a GaN film when a relative sensitivity factor is used. The changes in
69
Ga
−
intensity from repeat measurements have been determined to be affected by the instrument vacuum condition, ion energy distribution, sample charging, and type of sample holder used in the measurement.