Al-implantation induced damage in 4H-SiC

Abstract

Ion implantation of 4H-SiC is one of the crucial steps in the fabrication of power devices. This process results in the generation of electrically active defects both in the implanted region and beyond. In this work, we explore the defects created during Al-ion implantation and post implantation annealing using low-energy muon spin rotation (LE-𝜇SR) spectroscopy and deep level transient spectroscopy (DLTS). Two sets of samples, exposed to low fluence (LF) and high fluence (HF) of Al, are examined with and without annealing. The results reveal that defects induced by Al implantation extend deep into the semiconductor, far beyond the implanted region, thus influencing the electrical properties of SiC material. The LF samples exhibit a LE-𝜇SR signature that points to a carbon vacancy (𝑉𝒸) concentration in the range of 1 × 10¹⁵ to 1 × 10¹⁹ cm⁻³. Further, DLTS measurements reveal defect levels associated with silicon vacancies (𝑉ₛᵢ) and carbon vacancies (𝑉𝒸) several μm away from the intended implantation region, indicating that Al implantation and subsequent high-temperature annealing impacts the SiC lattice in a substantial volume. The present study provides valuable insights into the near- surface and bulk effects of Al implantation in 4H-SiC, which is essential for optimizing semiconductor device performance in power electronics applications.