  The continuous technological development of electronic devices and the
introduction of new materials leads to ever greater demands on the fabrication
of semiconductor heterostructures and their characterization. This work focuses
on optimizing Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) depth
profiles of semiconductor heterostructures aiming at a minimization of
measurement-induced profile broadening. As model system, a state-of-the-art
Molecular Beam Epitaxy (MBE) grown multilayer homostructure consisting of
$^{\textit{nat}}$Si/$^{28}$Si bilayers with only 2 nm in thickness is
investigated while varying the most relevant sputter parameters. Atomic
concentration-depth profiles are determined and an error function based
description model is used to quantify layer thicknesses as well as profile
broadening. The optimization process leads to an excellent resolution of the
multilayer homostructure. The results of this optimization guide to a ToF-SIMS
analysis of another MBE grown heterostructure consisting of a strained and
highly purified $^{28}$Si layer sandwiched between two Si$_{0.7}$Ge$_{0.3}$
layers. The sandwiched $^{28}$Si layer represents a quantum well that has
proven to be an excellent host for the implementation of electron-spin qubits.
