Unlocking Nanoscale Dopant Secrets by Atom Probe Tomography for Next-Generation Semiconductors

Doping semiconductors plays a crucial role in metal-oxide-semiconductor (CMOS) technology, such as enhancing carrier concentration and altering the distribution of the electric field [1]. With the scaling down of devices combined with a transition to three‐dimensional transistors, precise and reliable quantification of the dopant distribution and its concentration at the nanoscale are critical. In this context, atom probe tomography (APT) has emerged as one of the most promising techniques to fulfill these needs [2].

APT offers three-dimensional (3D) compositional mapping with sub-nanometer spatial resolution of all the elements present. This involves carefully removing and shaping the specimen i.e., device, material of interest, into a needle-shaped specimen with an apex of approximately 100 nm which then enables controlled field evaporation of the atoms to be performed. The evaporation is triggered by either a voltage or laser pulse, and the evaporated ions collected on a position-sensitive detector. By reversing the projection of the detected ions, a tomographic reconstruction of the specimen is achieved, enabling detailed 3D quantitative analysis. However, like all metrology techniques still in their infancy, there are still challenges to overcome. These include compositional inaccuracies and reconstruction artifacts due to field evaporation mechanism and reconstruction algorithm.

In this project, you will work with state-of-the-art equipment (APT LEAP5000XR and the latest generation APT tool: Invizo6000) to quantify the composition and dopant distribution within highly P doped Si currently being explored for next generation technologies. For the dopant distribution analysis, you will utilize versatile data mining algorithms (e.g., radial distribution, frequency distribution) on reconstructed datasets where different reconstruction approaches to reveal the local chemical environment of the dopants are applied. Depending on your interest, this project can be further enriched with simulations. Ultimately, the outcome of your project aims to expand the knowledge and the application of 3D-APT characterization.

[1]        W.K. Yeoh, S.-W. Hung, S.-C. Chen, Y.-H. Lin, and J.J. Lee, Surface and Interface Analysis, 52, 318–323 (2020).
[2]        B. Gault, A. Chiaramonti, O. Cojocaru-Mirédin, P. Stender, R. Dubosq, C. Freysoldt, S.K. Makineni, T. Li, M. Moody, and J.M. Cairney, Nature Reviews Methods Primers, 1, 51 (2021).

Type of Project: Combination of internship and thesis; Internship; Thesis 

Master's degree:  Master of Science; Master of Engineering Science; Master of Engineering Technology 

Master program: Physics; Nanoscience & Nanotechnology; Computer Science 

Duration: min. 6 months 

Supervisor: Claudia Fleischmann 

Supervising scientist: Richard Morris 

For more information or application, please contact Jhao-Rong Lin (jhao-rong.lin@imec.be).

Only for self-supporting students.