Laser endotaxy in silicon carbide and PIN diode fabrication

A laser solid phase diffusion technique has been utilized to fabricate endolayers in n-type 6H-SiC substrates by carbon incorporation. X-ray energy dispersive spectroscopic analysis shows that the thickness of the endolayer is about 100 nm. High resolution transmission electron microscopic images indicate that the laser endotaxy process maintains the crystalline integrity of the substrate without any amorphization. The resistivity of the endolayer formed in a 1.55 Ω cm silicon carbide wafer segment was found to be 1.1×105 Ω cm, which is sufficient for device fabrication and isolation. Annealing at 1000 °C for 10 min to remove hydrogen resulted in a resistivity of 9.4×104 Ω cm. The endolayer and parent silicon carbide epilayer were doped with aluminum using a laser doping technique to create p-regions on the top surfaces of the substrates in order to fabricate p-type-intrinsic type-n-type (PIN) diodes. The current-voltage characteristics of these diodes were compared with other PIN diodes fabricated using epilayers and other doping techniques.