High-Dose Phosphorus-Implanted 4H-SiC: Microwave and Conventional Post-Implantation Annealing at Temperatures ≥1700°C

• Published in: Journal of electronic materials 2012-03, Vol.41 (3), p.457-465
• Main Authors: Nipoti, R., Nath, A., Qadri, S.B., Tian, Y-L., Albonetti, C., Carnera, A., Rao, Mulpuri V.
• Format: Article
• Language: English
• Subjects: Annealing; Applied sciences; Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed matter: structure, mechanical and thermal properties; Electronics; Electronics and Microelectronics; Exact sciences and technology; Instrumentation; Ion radiation effects; Materials; Materials Science; Optical and Electronic Materials; Phosphorus; Physical radiation effects, radiation damage; Physics; Solid State Physics; Structure of solids and liquids; crystallography; Temperature effects; Transplants & implants
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-011-1794-7

Semi-insulating 4H-SiC ⟨0001⟩ wafers have been phosphorus ion implanted at 500°C to obtain phosphorus box depth profiles with dopant concentration from 5 × 10 19  cm −3 to 8 × 10 20  cm −3 . These samples have been annealed by microwave and conventional inductively heated systems in the temperature range 1700°C to 2050°C. Resistivity, Hall electron density, and Hall mobility of the phosphorus-implanted and annealed 4H-SiC layers have been measured in the temperature range from room temperature to 450°C. The high-resolution x-ray diffraction and rocking curve of both virgin and processed 4H-SiC samples have been analyzed to obtain the sample crystal quality up to about 3  μ m depth from the wafer surface. For both increasing implanted phosphorus concentration and increasing post-implantation annealing temperature the implanted material resistivity decreases to an asymptotic value of about 1.5 × 10 −3  Ω cm. Increasing the implanted phosphorus concentration and post-implantation annealing temperature beyond 4 × 10 20  cm −3 and 2000°C, respectively, does not bring any apparent benefit with respect to the minimum obtainable resistivity. Sheet resistance and sheet electron density increase with increasing measurement temperature. Electron density saturates at 1.5 × 10 20  cm −3 for implanted phosphorus plateau values ≥4 × 10 20  cm −3 , irrespective of the post-implantation annealing method. Implantation produces an increase of the lattice parameter in the bulk 4H-SiC underneath the phosphorus-implanted layer. Microwave and conventional annealing produce a further increase of the lattice parameter in such a depth region and an equivalent recovered lattice in the phosphorus-implanted layers.