Cw. Magee et Mr. Frost, RECENT SUCCESSES IN THE USE OF SECONDARY-ION MASS-SPECTROMETRY IN MICROELECTRONICS MATERIALS AND PROCESSING, International journal of mass spectrometry and ion processes, 143, 1995, pp. 29-41
Citations number
7
Categorie Soggetti
Spectroscopy,"Physics, Atomic, Molecular & Chemical
Secondary ion mass spectrometry (SIMS) has been used for over 20 years
by the microelectronics industry to determine in-depth distributions
of dopants and impurities which become incorporated into semiconductor
materials. SIMS not only has extremely high sensitivity (sub-part per
million for almost all elements), but inherent in the secondary ion f
ormation process is the ability to determine in-depth elemental distri
butions. While SIMS appears to be an ideal depth profiling technique,
in reality, it has had many drawbacks in the past. Three of them are t
he following. (1) Sentitivities can vary from element to element, and
from one matrix to another. (2) Reliable profiles within the top 100 A
ngstrom of the sample are difficult to obtain due to changing ion yiel
ds within this region. (3) Atomic mixing in the sample lattice due to
energetic ion bombardment can distort sharply falling in-depth element
al distributions. The aim of this paper is to show how SIMS has recent
ly overcome these problems to allow us to obtain accurate depth profil
es within the top 100 Angstrom of a sample with minimal matrix effects
on sensitivities. We show examples from three areas: (1) analysis of
shallow dopants and junctions in semiconductors; (2) analysis of 100 A
ngstrom thick SiO2 gate dielectric films; (3) analysis of surface cont
amination on Si wafer surfaces. All of these problems are of intense c
urrent interest and are at the forefront of SEMATECH's perceived need
for Si semiconductor characterization efforts into the next century.