Laser doping of chromium as a double acceptor in silicon carbide with reduced crystalline damage and nearly all dopants in activated state
✍ Scribed by Sachin Bet; Nathaniel Quick; Aravinda Kar
- Publisher
- Elsevier Science
- Year
- 2008
- Tongue
- English
- Weight
- 779 KB
- Volume
- 56
- Category
- Article
- ISSN
- 1359-6454
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✦ Synopsis
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 Â 10 19 cm À3 in 6H-SiC and 1.42 Â 19 19 cm À3 in 4H-SiC), exceeding the equilibrium limit (3 Â 10 17 cm À3 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 E v + 0.80 eV in 4H-SiC and E v + 0.45 eV in 6H-SiC. The Hall effect measurements showed that the hole concentration (1.942 Â 10 19 cm À3 ) is almost twice the average Cr concentration (1 Â 10 19 cm À3 ), 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.