Ohmic contacts on silicon carbide: The first monolayer and its electronic effect

Abstract

We demonstrate that origin of the long-standing contact issue in silicon carbide devices can be understood and technologically manipulated at the atomic level. Using advanced transmission electron microscopy, we attribute qualitatively the formation of ohmic contacts to silicon carbide to an epitaxial, coherent, and atomically ordered interface. Quantitatively, first-principles calculations predict that this interface can trap an atomic layer of carbon and hence enable lowered Schottky barrier and enhanced quantum electron transport. The combined experimental and theoretical studies performed provide insight into the complex electronic and electric effects of the buried contact interface, which are fundamental for improving the contact in future electronics based on wide-band-gap semiconductors such as silicon carbide and diamond.

Anisotropy of the resistivity and charge-carrier sign in nanolaminated Ti2AlC: Experiment andab initiocalculations

“…Of special interest are the titanium-based compounds, intensively investigated for high temperature ohmic contacts on wide gap semiconductors. [7][8][9][10] MAX phase electronic properties and especially the anisotropy resulting from the nanolaminated structure is not yet fully understood. Although intensively studied, it remains a complex issue since the majority of transport experiments were performed on polycrystalline samples, thereby averaging the basal plane and c-axis transport properties.…”

Step-flow growth of nanolaminate Ti3SiC2 epitaxial layers on 4H-SiC(0 0 0 1)

“…In such electronic device applications, a challenge is the formation of ohmic contacts to the SiC, as well as the durability of the contacts when operated at elevated temperatures. High-temperature annealed Ti/Al contacts on p-type SiC have been reported to form Ti 3 SiC 2 [5-8], which is suggested to contribute to the ohmic behavior of the contacts [9][10][11].Formation of Ti 3 SiC 2 and subsequent ohmic behavior has also been reported for hightemperature annealed Ti-based contacts on n-type SiC [12,13]. Here, we investigate the growth of Ti 3 SiC 2 thin films on 4° off-cut 4H-SiC using DC magnetron sputtering from three sources.…”

“…In such electronic device applications, a challenge is the formation of ohmic contacts to the SiC, as well as the durability of the contacts when operated at elevated temperatures. High-temperature annealed Ti/Al contacts on p-type SiC have been reported to form Ti 3 SiC 2 [5][6][7][8], which is suggested to contribute to the ohmic behavior of the contacts [9][10][11].…”

Growth and characterization of epitaxial Ti3GeC2 thin films on 4H-SiC(0001)

“…Ti 3 SiC 2 is known to form after high temperature annealing of Ti-, and Ti/Albased contacts on SiC [6][7][8][9][10]. In recent publications, we have reported on the ohmic contact properties of sputter-deposited Ti 3 SiC 2 on 4H-SiC(0001), and investigated the step-flow growth mode of epitaxially grown Ti 3 SiC 2 layers on SiC [11,12].…”