TPA-TCT: Enabling Non-Destructive 3D Semiconductor Inspection and Characterization Through Two-Photon Absorption

Current semiconductor inspection techniques rarely achieve truly non-destructive three-dimensional mapping of device structures, typically limited by destructive sample preparation, restricted penetration depth, or insufficient spatial resolution.

This presentation introduces a characterization technique combining optical and electrical methods for non-destructive 3D inspection, based on Two-Photon Absorption (TPA) and the Transient Current Technique (TCT). TPA uses a femtosecond fiber laser (Pulsar) operating below the semiconductor bandgap, interacting only within the focal volume due to its nonlinear nature. TCT measures the transient electrical response from carrier transport, extracting local parameters such as carrier lifetime, drift velocity, and charge collection efficiency.

Combining TPA and TCT yields a non-destructive electro-optical tool for semiconductor inspection, enabling 3D mapping of internal defects, doping non-uniformities, and electric field distribution without sectioning the device. It is well suited for monitoring device aging and degradation under harsh conditions, including high radiation exposure, elevated temperatures, and chemically aggressive environments.

About the presenter
Dariusz Swierad, Ph.D., is an expert in ultrafast laser technology and currently serves as the chief sales officer at FYLA LASER. He combines a deep technical background in quantum physics with extensive experience in the industrial photonics market.

Before joining FYLA, he spent seven years at Fluence Technology, where he played a pivotal role in bridging the gap between advanced research and development and the successful industrial application of next-generation femtosecond lasers. Earlier in his career, he led the development of a miniaturized atomic clock as a project science lead at Teledyne e2v, and expanded the market for quantum and terahertz applications as a field sales engineer at TOPTICA Photonics.

Swierad holds a doctorate in physics from the University of Birmingham, where he contributed to the development of ultrastable laser systems for initiatives including the Space Optical Clock project, and a B.Sc. in Theoretical Physics from Nicolaus Copernicus University in Torun.