Laser Direct-Metallization of Silicon Carbide without Metal Deposition

Abstract

AbstractLaser direct-write (LDW) is used forin-situmetallization in single crystal 4H- and 6H-SiC wafers without metal deposition. Nanosecond-pulsed Nd:YAG (λ= 1064 and 532 nm) and excimer (λ = 193, 248 and 351 nm) lasers are utilized to create metal-like conductive phases in both n-type and p-type SiC wafers. Frequency-doubled Nd:YAG irradiation(Ephoton< Eg) induces a carbon rich conductive phase due to thermal decomposition of SiC. However, pulsed excimer laser irradiation (Ephoton> Eg) produces a Si- rich conductive phases due to carbon photo ablation. The Schottky barrier heights (SBH) between the laser-metallized layer and the original n-type SiC (ND= 1018cm-3) is determined to be 0.8 eV and 1.0 eV by the current-voltage and capacitance-voltage measurements at room temperature, respectively. Linear transmission line method pattern is directly fabricated in n-type doped (ND=1018cm-3) SiC substrate by pulsed laser irradiation allowing to extract the specific contact resistance (rc)of the laser fabricated metal-like tracks (rc= 0.04-0.12 Ωcm2).The specific contact resistance is unchanged after annealing up to 3 hrs at 950°C.