Plasma Profiling Time-of-Flight Mass Spectrometry for Fast Elemental Analysis of Semiconductor Structures with Depth Resolution in the Nanometer Range

TL;DR

Plasma profiling time-of-flight mass spectrometry (PP-TOFMS) provides rapid, high-resolution elemental depth profiling of semiconductor structures, outperforming traditional methods in speed, depth resolution, and elemental information without extensive sample preparation.

Contribution

This study demonstrates that PP-TOFMS can resolve semiconductor layer structures more than 500 nm deep with high accuracy, offering a faster and more comprehensive alternative to conventional micro- and nano-analysis techniques.

Findings

PP-TOFMS resolves layer structures over 500 nm deep.

Achieves about 10% relative elemental composition accuracy.

Provides faster, more detailed elemental profiles without extensive sample prep.

Abstract

Plasma profiling time of flight mass spectrometry (PP-TOFMS) has recently gained interest, as it enables the elemental profiling of semiconductor structures with high depth resolution in short acquisition times. As recently shown by Tempez et al., PP-TOFMS can be used to obtain the composition in the structures for modern field effect transistors [1]. There, the results were compared to conventional SIMS measurements. In the present study, we compare PP-TOFMS measurements of an Al-/In-/GaN quantum well multi stack to established micro- and nano-analysis techniques like cathodoluminescence (CL), scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). We show that PP-TOFMS is able to resolve the layer structure of the sample even more than 500 nm deep into the sample and allows the determination of a relative elemental composition with an accuracy of about 10 rel. %. Therefore, it is an extremely rapid alternative method to obtain semiconductor elemental depth profiles without expensive and time consuming sample preparation as it is needed for TEM. Besides, PP-TOFMS offers better depth resolution and more elemental information than for example electrochemical capacitance-voltage (ECV), as the acquisition of all elements occurs in parallel and not only electrically (ECV) or optically (CL) active elements are observed.