Dopants are elements deliberately added to semiconductor materials to control the electrical characteristics of the material. Concentrations are typically in the low atomic% range down to parts per million (ppm). Dopant concentration and distribution are key characteristics in determining electrical performance. Analytical techniques are frequently used to compare the doping profile in a device of interest with the measured electrical performance.
Secondary Ion Mass Spectrometry (SIMS) and Low Energy X-ray Emission Spectrometry (LEXES) can be used to accurately determine implant dose, and precisely compare doses between wafers. LEXES can also be used to map the implanted dose across wafers up to 300mm in size.
SIMS can be used to characterize the profile shape of ion implants and contaminants. If the dopant is electrically active, Spreading Resistance Profiling (SRP) can be used.
SIMS can be used to accurately measure the concentration of dopants as a function of depth in silicon, compound semiconductors, photovoltaic and LED materials.