Schottky Barrier Height Dependence on the Metal Work Function for p-type 4H-Silicon Carbide
Authors: Lee, S.K.; Zetterling, C.M.; Östling, M.
Source: Journal of Electronic Materials, Volume 30, Number 3, 1 March 2001 , pp. 242-246(5)
Abstract:We investigated Schottky barrier diodes of several metals (Ti, Ni, and Au) having different metal work functions to p-type 4H-SiC (0001) using I-V and C-V characteristics. Contacts showed excellent Schottky behavior with stable ideality factors of 1.07, 1.23, and 1.06 for Ti, Ni, and Au, respectively, in the range of 24°C to 300°C. The measured Schottky barrier height (SBH) was 1.96, 1.41, and 1.42 eV for Ti, Ni, and Au, respectively, in the same temperature range from I-V characteristics. Based on our measurements for p-type 4H-SiC, the SBH (φBp) and metal work functions (φm ) show a linear relationship of φBp = 4.58 - 0.61φm and φBp = 4.42 - 0.54φm for I-V and C-V characteristics at room temperature, respectively. We observed that the SBH strongly depends on the metal work function with a slope (S ≡ φBp/φm) of 0.58 even though the Fermi level is partially pinned. We found the sum of the SBH (φBp + φBn= Eg) at room temperature for nand p-type 4H-SiC to be 3.07 eV, 3.12 eV, and 3.21 eV for Ti, Ni, and Au, respectively, using I-V and C-V measurements, which are in reasonable accord with the Schottky-Mott limit.
Document Type: Research article
Publication date: 2001-03-01