Material Characterization of 4H-SiC - Influence of Protection Layer Thickness on Dopant Depth During Ion-Implantation

The overall goal of the present research is to understand the behaviour of dopants in 4H-SiC (4H- Silicon Carbide). 4H-Silicon Carbide (4H-SiC) is renowned for its high thermal stability, wide bandgap, and suitability for high-power and high-temperature electronic applications. [1–2] This study focuses on analyzing the distribution and diffusion behaviour of dopants in 4H-SiC, as well as the resulting surface modifications, following aluminum (Al) ion implantation and subsequent post-implantation annealing. Based on our selected implantation parameters (dose, energy, and temperature) and post-annealing conditions (temperature and time), Dynamic Secondary Ion Mass Spectrometry (SIMS) measurements are being conducted to acquire quantitative depth profiles of the implanted aluminum. These measurements enable a detailed assessment of the aluminum distribution, including the identification of diffusion tails and potential segregation effects, under our specific processing conditions. Comparative analysis of the profiles before and after thermal annealing provides critical insights into dopant activation behaviour, redistribution mechanisms, and the influence of annealing on the stability of the dopant profile. In parallel, TOF-SIMS is used to investigate surface effects such as dopant clustering, and contamination because high-temperature annealing can cause sublimation of silicon, resulting in a carbon-rich surface layer that may lead to carbon agglomeration. In addition, Al dopant may accumulate near the surface at high-temperature, and the presence of trace oxygen or moisture may result in surface oxidation. TOF-SIMS plays a crucial role in identifying these surface changes by enabling high-sensitivity detection of carbon build-up, residual aluminum, oxygen, and other contaminants. This enhances our understanding of post-annealing surface chemistry in Al-implanted 4H-SiC. Using both SIMS methods gives a clear picture of how dopants behave in SiC and helps improve doping processes. This highlights SIMS as a key tool for refining implantation and annealing steps in 4H-SiC devices.