SIMS analysis

What is SIMS analysis used for?

SIMS is widely used to analyze a broad range of solid materials, including semiconductors, metals, oxides, and polymers. It is commonly used in the microelectronics and semiconductor industry to investigate doping profiles, trace contaminations, diffusion processes, and multilayer structures. The technique is especially useful for characterizing thin films deposited using methods such as Chemical Vapor Deposition (CVD), Atomic Layer Deposition (ALD), and Physical Vapor Deposition (PVD).

One of the main advantages of SIMS is its ability to perform high-resolution compositional depth profiling, making it suitable for analyzing ultra-thin films and multilayer stacks with nanometer-scale precision. In addition, SIMS can detect and quantify all elements and isotopes, including hydrogen (H), in the parts-per-billion (ppb) and even parts-per-trillion (ppt) range. The technique can detect variations in composition across interfaces, making it valuable for studying diffusion, segregation, and interfacial layers.

While SIMS is an extremely powerful analytical tool, certain factors can affect its measurement accuracy. Matrix effects, preferential sputtering, and surface charging (especially in insulating materials) can influence ion yield and require careful calibration and interpretation. By optimizing analysis conditions, SIMS enables highly detailed chemical and isotopic insights into complex material systems.

What is the working principle of SIMS?

SIMS operates by bombarding a sample's surface with a focused beam of high-energy primary ions, such as oxygen (O₂⁺) or caesium (Cs⁺). These primary ions transfer momentum to the sample atoms, ejecting secondary ions from the surface. The secondary ions are then collected and analyzed by a mass spectrometer to determine the sample's elemental, isotopic, and molecular composition.

During depth profiling, material is continuously removed from the surface, and variations in the composition are recorded, allowing for the analysis of interfaces, diffusion profiles, and ultra-thin layers. The depth resolution of SIMS depends on the energy of the primary ion beam. By adjusting the beam, we can create compositional depth profiles anywhere from a few nanometres to several microns.

Examples of SIMS results

Static vs. dynamic SIMS

SIMS can be operated in two primary modes: static and dynamic. While both modes work on the same principle, they vary greatly in their primary ion beam type, equipment, and information that we can obtain from them. 

• Static SIMS (also known as ToF-SIMS) uses a low ion dose to probe only the topmost atomic layers (1-2 nm), allowing for high-sensitivity analysis of molecular and elemental composition on the outermost surface of the sample.

• Dynamic SIMS (also known as SIMS) uses a continuous ion beam to progressively remove material from the surface, enabling high-resolution depth profiling of thin films, dopant distributions, and multilayer structures.

Need SIMS analyses?

Measurlabs offers laboratory testing with SIMS and ToF-SIMS techniques, with the capacity to handle large batches of samples and provide volume discounts for bulk orders. With fast turnaround times, access to various device types, and personalized service from method experts, Measurlabs is a trusted partner for over 700 clients in various industries, including Okmetic and other industry leaders in the semiconductor field.