Impact of Carbon Implantation and Post-Annealing on Deep Level Defects and Carrier Lifetimes in n-Type 4H-SiC Epilayers

Impact of carbon implantation and post-annealing temperature on deep level defects and carrier lifetimes in n-type 4H-SiC epilayers are investigated. After carrying out carbon implantation into the shallow surface layer of 500 nm and subsequent annealing, the surface roughness of the epilayer increases with annealing temperature. Carrier lifetimes show negative dependence on the annealing temperature while deep level defect concentrations show a positive trend. When the annealing temperature reaches 1600°C, Z<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2</inf> center concentration is 8.53×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup> cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3</sup> and carrier lifetime is 2.03 μs in the 100 μm 4H-SiC epilayers. Properties of Z<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2</inf> center in the crystal are discussed based on the experimental results. The results demonstrate that carbon implantation/annealing process is crucial to decrease surface recombination and eliminate the deep level centers in the epilayers.