Depth profile of doping concentration in thick (> 100 μm) and low-doped (< 4 × 1014 cm−3) 4H-SiC epilayers

The depth profiles of n-type doping concentration in thick (>100 μm) and low-doped (<; 4 × 10
¹⁴
cm
^-3
) 4H-SiC epilayers grown by chemical vapor deposition (CVD) were investigated. The variation in doping concentration during epitaxial growth are considered to be caused by: (1) variation in gas flow due to parasitic deposition, (2) variation in precursor decomposition rate due to change in reactor temperature, (3) variation in dopant incorporation rate due to change in wafer temperature, and (4) variation in supply of background dopants. By controlling all these parameters, a constant depth profile in thick (> 100um) epilayers was realized.