Chemical and structural analyses of the titanium nitride/alpha (6H)-silicon carbide interface

Abstract

Ion-assisted reactive evaporation (IARE) using low-energy (100 eV) nitrogen ions was employed to deposit TiN films onto the vicinal Si-terminated (0001) face of α(6H)-SiC single crystals at 350 °C in an ultrahigh vacuum chamber operated at a working pressure of 2×10−4 Torr. The initial exposure of the SiC surface to nitrogen ions for a 2-min period resulted in Si–N bonding. This exposure was also an important step in attaining ohmic contact properties at low temperature, and the formation of a thin (≊5–15 Å) amorphous layer at the interface. The disorder was maintained after the deposition of 5 Å of TiN. The TiN contacts were ohmic after deposition; they showed little change in microstructural or electrical properties after annealing at 450, 550, and 600 °C for 15–30 min. The results of this research indicate that a metal–insulator–semiconductor structure was responsible for obtaining the contact properties.

Study of contact resistivity, mechanical integrity, and thermal stability of Ti/Al and Ta/Al ohmic contacts to n-type GaN

“…A similar mechanism has been proposed for TiN contacts to (6H)-SiC in which a thin amorphous layer of Si x N y was detected at the interface. 13 Since an AlN layer has been observed in Ti/Al and Pd/Al contacts, it is possible that the same mechanism is at work in Ta/Al contacts to allow ohmic contact formation, considering the similarities in the results of Ti/Al, Pd/Al, and Ta/Al contacts.…”

Characteristics of 21H-SiC Thin Film-Based Schottky Barrier Diodes Using TiN Contacts

“…16 Wang et al indicated that the interfacial charge polarization and strong coupling of the interfacial electronic states for lowering of Schottky barrier height of the interface leads to the ohmic contact formation of TiN to SiC. 17 TiN is also known to form titanium silicides and titanium carbides with SiC at high temperatures, 18 which act as a diffusion barrier and exhibit both Schottky and ohmic contact behavior, 19 depending on the deposition conditions. Glass et al studied the effect of TiN contacts on 6H-SiC formed by reactive evaporation (RE), ion-assisted reactive evaporation (IARE), and a process where IARE is preceded by nitriding the SiC surface (IARE-N).…”

“…Glass et al studied the effect of TiN contacts on 6H-SiC formed by reactive evaporation (RE), ion-assisted reactive evaporation (IARE), and a process where IARE is preceded by nitriding the SiC surface (IARE-N). 19 They found that TiN films deposited by RE, and IARE methods at room temperature followed by annealing at 600°C are rectifying in nature due to the low reactivity of the carbide surface and nitrogen. However, the films deposited using IARE-N are ohmic in nature because of the formation of an insulating interfacial layer of a-SiN.…”

“…However, the films deposited using IARE-N are ohmic in nature because of the formation of an insulating interfacial layer of a-SiN. 19 It is also observed that the presence of an intermediate layer (Si 3 N 4 ) between metal and SiC leads to the formation of an MIS structure, resulting in a decrease in barrier height and ideality factor. 20 The results on 6H, 4H, 3C SiC-based SBDs reveal that variation of Schottky parameters with temperature can be correlated with the presence of inhomogeneity at the metal/SiC interface, variation in local interfacial structure, and roughness at an atomic level in the metal/semiconductor interface.…”

Growth, surface morphology, optical properties and electrical resistivity of ɛ-TiNx (0.4<x≤0.5) films

“…[1][2][3][4][5] Stoichiometric crystalline TiN is a good conductor of electricity, is useful as a diffusion barrier material and exhibits gold-like colour, whereas amorphous or nitrogen deficient TiN is a very good insulator [6][7][8]. Amorphous TiN films exhibit high electrical resistivity, high transmission of light in the visible region of wavelengths and a lack of metallic brilliance.…”