Laser doping of chromium as a double acceptor in silicon carbide with reduced crystalline damage and nearly all dopants in activated state Original Research Article

Chromium, a p-type dopant, has been incorporated into silicon carbide by laser doping. Secondary ion mass spectrometric data revealed enhanced solid solubility (2.29 × 1019 cm−3 in 6H–SiC and 1.42 × 1919 cm−3 in 4H–SiC), exceeding the equilibrium limit (3 × 1017 cm−3 in 6H–SiC above 2500 °C). The roughness, surface chemistry and crystalline integrity of the doped sample were examined by optical interferometry, energy dispersive X-ray spectrometry and transmission electron microscopy, respectively, and showed no crystalline disorder due to laser heating. Deep-level transient spectroscopy confirmed Cr as a deep-level acceptor with activation energies Ev + 0.80 eV in 4H–SiC and Ev + 0.45 eV in 6H–SiC. The Hall effect measurements showed that the hole concentration (1.942 × 1019 cm−3) is almost twice the average Cr concentration (1 × 1019 cm−3), confirming that almost all of the Cr atoms were completely activated to the double acceptor state by the laser-doping process without requiring any additional annealing step.