A Comparative Optimization of Electrical Properties and Surface Morphology of Ti/Al/Ta/Au Ohmic Contacts in AlGaN/GaN HEMTs on Si(111), Sapphire, 4H-SiC Substrates

Sung Jin Cho; Cong Wang; Nam Young Kim

doi:10.4028/www.scientific.net/AMR.538-541.2207

Paper Titles

Study on the Effect Factors of the Removal Rate of Permanganate Index in the Filtration Process
p.2190

The Influence of Ethanol Extraction in the High Temperature Steaming Induced Discoloration Process of Locust (Robinia pseudoacacia) Wood
p.2194

Study of PP/nano-TiO₂ Composites on Plastic Mechanism after Microwave Irradiation
p.2199

Effect of B₂O₃ Substituted for CaF₂ as Fluxing Agent on Melting Temperature of Converter Slag
p.2203

A Comparative Optimization of Electrical Properties and Surface Morphology of Ti/Al/Ta/Au Ohmic Contacts in AlGaN/GaN HEMTs on Si(111), Sapphire, 4H-SiC Substrates
p.2207

Calculated Optimal Cuts for SAW Applications of LGS Crystal
p.2211

Mechanism of Modified Sponge Iron Deoxygenization and its Application for High Pressure Boiler Feed Water
p.2215

Fabrication and Sound Absorption Properties of Porous Fe_0.2(Co₂₀Ni₈₀)_0.8 Alloy Microfibers
p.2220

Aligned MWCNT-Reinforced Bulk Epoxy-Matrix Composites by Dielectrophoretic Force
p.2224

HomeAdvanced Materials ResearchAdvanced Materials Research Vols. 538-541A Comparative Optimization of Electrical...

A Comparative Optimization of Electrical Properties and Surface Morphology of Ti/Al/Ta/Au Ohmic Contacts in AlGaN/GaN HEMTs on Si(111), Sapphire, 4H-SiC Substrates

Abstract:

In the process of characterizing AlGaN/GaN HEMTs on Si (111), Sapphire, 4H-SiC substrates, various Rapid Thermal Annealing (RTA) conditions for the Ti/Al/Ta/Au ohmic contact process and the resulting surface analysis have been investigated. In order to achieve a low ohmic contact resistance (RC) and a high quality surface morphology, we tested seven steps (800 °C to 920 °C) annealing temperatures and two steps (15, 30 sec) annealing times. According to these annealing temperatures and times, the optimal ohmic resistance of 3.62 × 10^-6 Ohm • cm² on Si(111) substrate, 9.44 × 10^-6 Ohm • cm² on Sapphire substrate and 1.24 × 10^-6 Ohm • cm² on 4H-SiC substrate are obtained at an annealing temperature of 850 °C and an annealing time of 30 sec, 800 °C and an annealing time of 30 sec and 900 °C and an annealing time of 30 sec, respectively. The surface morphologies of the ohmic contact metallization at different annealing temperatures are measured using an Atomic Force Microscope (AFM). AFM morphology Root Mean Square (RMS) level determines the relationship of the annealing temperature and the annealing time for all of the samples. According to these annealing temperatures and times, the optimal ohmic surface RMS roughness of 13.4 nm on Si(111) substrate, 3.8 nm on Sapphire substrate and 2.9 nm on 4H-SiC substrate are obtained at an annealing temperature of 850 °C and an annealing time of 30 sec, 800 °C and an annealing time of 30 sec and 900 °C and an annealing time of 30 sec, respectively.