What’s Under the Hood of a LiDAR System? How SIMS Analyzes Critical Optical Materials

SIMS is a surface level analysis technique that reveals the chemical makeup of materials with astonishing sensitivity. It works by bombarding a material’s surface with a focused ion beam, which dislodges atoms from the surface. These ejected atoms, now ionized, are measured by a mass spectrometer, allowing scientists to identify and quantify the elements present in the material. What makes SIMS unique is its ability to detect incredibly low concentrations, down to parts per billion, of dopants, contaminants, or trace metals, and to map those elements with nanometer precision through the depth of a sample.  

In the world of LiDAR, where precision is everything, this level of detail matters. Moreover, it’s an essential piece. The laser diodes at the heart of these systems are often made from materials such as gallium arsenide (GaAs) or indium phosphide (InP), which need carefully controlled levels of dopants to function optimally. Even slight variations in composition can affect the laser’s wavelength, power, output, and even their reliability. SIMS helps manufacturers ensure that dopant concentrations are exactly where they need to be, not too shallow, not too deep, and not drifting over time. 

Just as critical, SIMS can detect trace contamination that may originate from the fabrication environment or raw materials. Even minute impurities can compromise laser performance or long-term stability. SIMS provides accurate layer thickness measurements, confirming that each deposited layer meets design specifications and supports the intended optical and electrical behavior of the diode.  

The trend toward smaller, more integrated LiDAR systems is also making SIMS even more relevant. As companies move toward solid-state designs that eliminate the need for rotating sensors by integrating optics and electronics into a single chip, the margins for error shrink dramatically. SIMS plays a vital role in verifying that these miniaturized systems still meet their performance targets, detecting issues like ion diffusion across layers, interfacial defects, or contamination during processing.