TY - JOUR
T1 - Electrical characterization of titanium-based ohmic contacts to 4h-silicon carbide for high-power and high-temperature operation
AU - Lee, Sang Kwon
AU - Zetterling, Carl Mikael
AU - Östling, Mikael
AU - Moon, Byung Moo
PY - 2002/4
Y1 - 2002/4
N2 - We report on titanium-based ohmic contacts (titanium carbide, titanium tungsten, and titanium) on both highly doped epilayers (n+ and p+) and Al-ion-implanted layers. The TiC contact layer was epitaxially grown on epilayers as well as an Al-ion-implanted layers of 4H-SiC by co-evaporation Ti and C60 under an ultra-high vacuum condition at low temperature (<500 °C). For comparison and long-term stability test, we also deposited TiW (weight ratio 30: 70) ohmic contacts to p- And n-type epilayers of 4H-SiC. The specific contact resistances (ρc) were found to be as low as 5 × 10-6, 2 × 10-5, 2 × 10-5, 3 × 10-4, 4 × 10-5 and 1 × 10-4 Ωcm2 for TiC contacts to n+ epilayers, p+ epilayers, and Al-ion-implanted layers, Ti contacts to p+ epilayers, and TiW contacts to p+ and to n+ epilayers, respectively, by using linear transmission line method (TLM) measurements. During the long-term reliability tests in a vacuum chamber, we found that evaporated Au capping layers helped to keep the contacts from degrading.
AB - We report on titanium-based ohmic contacts (titanium carbide, titanium tungsten, and titanium) on both highly doped epilayers (n+ and p+) and Al-ion-implanted layers. The TiC contact layer was epitaxially grown on epilayers as well as an Al-ion-implanted layers of 4H-SiC by co-evaporation Ti and C60 under an ultra-high vacuum condition at low temperature (<500 °C). For comparison and long-term stability test, we also deposited TiW (weight ratio 30: 70) ohmic contacts to p- And n-type epilayers of 4H-SiC. The specific contact resistances (ρc) were found to be as low as 5 × 10-6, 2 × 10-5, 2 × 10-5, 3 × 10-4, 4 × 10-5 and 1 × 10-4 Ωcm2 for TiC contacts to n+ epilayers, p+ epilayers, and Al-ion-implanted layers, Ti contacts to p+ epilayers, and TiW contacts to p+ and to n+ epilayers, respectively, by using linear transmission line method (TLM) measurements. During the long-term reliability tests in a vacuum chamber, we found that evaporated Au capping layers helped to keep the contacts from degrading.
KW - 4H-silicon carbide
KW - Long-term reliability
KW - Ohmic contacts
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U2 - 10.3938/jkps.40.572
DO - 10.3938/jkps.40.572
M3 - Article
AN - SCOPUS:0036012664
SN - 0374-4884
VL - 40
SP - 572
EP - 576
JO - Journal of the Korean Physical Society
JF - Journal of the Korean Physical Society
IS - 4
ER -