Surface Properties and Electrical Characteristics of Rapid Thermal Annealed 4H-SiC

摘要

Structural and electrical properties of implanted 4H-SiC annealed in a modified production type RTP system have been examined. Aluminum was implanted into n-type 4H-SiC epitaxial layer at different energies and doses in order to obtain a box shaped profile. Dopant annealing was performed in argon and for some wafers in nitrogen ambient at temperatures between 1600℃ and 1740℃ by RTP. Slightly increasing surface roughness with annealing time and temperature can be observed for RTA samples, but the rms values reveal that the surface topography of the RTA samples stays relatively smooth which can be attributed to an effective suppression of step bunching phenomena. Satisfying sheet resistance of about 60 kΩ/□ for Al implanted 4H-SiC wafers with a dose of 1.26x10~(15)cm~(-2) was obtained. Annealing at 1700℃/120 s showed lower sheet resistance than the high-temperature/short-time annealing at 1740℃/20 s.