Measure and analysis of 4H-SiC Schottky barrier height with Mo contacts

Abstract

Current–voltage (I–V) and capacitance–voltage (C–V) characteristics of Schottky Mo/4H-SiC diodes have been measured and analyzed as a function of temperature between 80 and 400 K. The I–V characteristics significantly deviate from ideal characteristics predicted by the thermionic emission model because of the inhomogeneity of Schottky contact. After a brief review of the different existing models, the main parameters (ideality factor, barrier height, and effective Richardson constant) of both diodes have been extracted in the frame of a Gaussian barrier height distribution model, whose mean and standard deviation are linearly dependent on voltage and temperature, as well as in the context of the potential fluctuation model. The results are compared with the values extracted by C–V and the values in the literature. A link is established between these two models. Diodes of different I–V characteristics, either identified as single barrier or double barrier, have been analyzed by Deep Level Transient Spectroscopy (DLTS) to investigate the deep level defects present. No noticeable difference has been found.

Effect of Different Sized Multi Walled Carbon Nanotubes on the Barrier Potential and Trap Concentration of Malachite Green Dye Based Organic Device

“…q is the charge of electron, V is the applied voltage, A is the device area, k is the Boltzmann's constant, T is absolute temperature, A* is the effective Richardson constant, n is the ideality factor and ϕ b is the barrier potential and IS is the saturation current [21][22][23][24][25][26][27].…”

Enhanced Non-Uniformity Modeling of 4H-SiC Schottky Diode Characteristics Over Wide High Temperature and Forward Bias Ranges

“…Modeling the inhomogeneous Schottky interface usually assumes the presence of multiple tiny zones (patches) with different barrier heights on the contact surface, which contribute variably to the total current according to the thermionic emission transport mechanism [1]- [19]. This parallel conduction theory is, thus, the cornerstone of all current non-uniformity models [3]- [13].…”

“…This parallel conduction theory is, thus, the cornerstone of all current non-uniformity models [3]- [13]. The most prominent assumes a Gaussian distribution of patches on a Schottky contact's surface [1], [5], [6], [12], [14]. While this approach was proven adequate for modeling devices over limited temperature ranges, it was quickly demonstrated that, at cryogenic temperatures, it is "in significant error" [7].…”

“…However, with the popularization and rapid development of wide-bandgap Schottky diodes, the maximum operating temperature for these devices was extended to well over the limits of silicon, allowing assessment of electrical behavior over very high domains. Under these conditions, the attempt to characterize devices at elevated temperatures with the devoted models has revealed glaring limitations in practicality and parameter interpretation [1], [3], [8]- [11], [13]. Specifically, it was empirically determined that, for wide enough investigated temperature intervals, the parameters produced by Tung's model have important variations and are only locally impactful, encumbering the extraction and deconvolution processes.…”

The Optimization of 3.3 kV 4H-SiC JBS Diodes

“…Theoretical considerations of the exact conduction mechanisms in the ON-state and the OFF-state have also been widely investigated, with Tung's description of thermionic field emission dominating the conduction of Schottky diodes being the basis of most attempts to exactly model both leakage current levels and ON-state performance [10], [11]. Over the past decade, industrial suppliers have moved away from high work function metals such as nickel (Ni) toward lower work function metals such as titanium (Ti) [12], [13] and molybdenum [14], [15], where a decrease in forward voltage drop has come at the expense of higher leakage currents. More recently, molybdenum nitride (MoN) has been selected as metal by companies for their low barrier height devices [16], [17], which were demonstrated to have even lower barrier heights.…”