An adapted method for analyzing 4H silicon carbide metal-oxide-semiconductor field-effect transistors

Abstract

Silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) are key devices for next-generation power electronics. However, accurate determination of device parameters from 3-terminal characteristics is hampered by the presence of interface traps. Here we present a method that, in contrast to previous evaluation schemes, explicitly considers those defects. A well-tractable parametrization of the SiC/SiO 2-specific interface trap spectrum is introduced that reflects the body of known data. With this ingredient, we develop an analysis that targets for an accurate determination of device parameters from simple 3terminal characteristics. For its validation, we investigate MOSFETs with significantly different defect densities. The resulting parameterscharge carrier density, mobility and threshold voltageare in excellent agreement with Hall effect investigations on the very same devices, avoiding systematic errors inherent to conventional evaluation techniques. With this adapted scheme, 4H-SiC power MOSFETs, even packaged, can be meaningfully characterized, speeding up innovation cycles in energy-saving power electronics.

Characterization of SiO2/4H-SiC Interfaces in 4H-SiC MOSFETs: A Review

“…Standard detection method C-ψ method Very recently, Hauck et al [44] presented an analytical method that overcomes some of the limits of many methodologies originally developed for silicon devices. In particular, their analytical model makes it possible to correct the underestimation of the charge carrier concentration and mobility.…”

“…On the other hand, the incorporation of elements of the II and III groups of the periodic table, B [7,44], Ba [45], Ca [60], La [54], Sr [60], has been investigated to explore other possible effects that explain the increase of MOSFET channel mobility. In fact, elements of the II and III groups cannot provide donors in the channel region, similar to the V group elements.…”

Surface passivation of germanium by atomic layer deposited Al2O3 nanolayers

“…The potential of Ge in these applications is hampered by a high density of electronic defects at its surface. In MOSFETs, these defects can lower the sub-threshold slope [6][7][8] and lead to a compromised carrier channel mobility [9,10], while in nanolasers [11][12][13] and solar cells [14,15] these defects can act as non-radiative recombination centers for electrons and holes which decrease the conversion efficiency. Surface passivation of Ge is essential to mitigate these effects.…”

Excellent surface passivation of germanium by a-Si:H/Al2O3 stacks

“…[15][16][17] In the aforementioned devices, whose surface-to-volume ratio is continuously increasing, defects at the interface between the semiconductor and the adjacent layer lead to electronic states in the bandgap, which can be detrimental to device performance. In field-effect transistors (FETs), these interface states can lower the sub-threshold slope [18][19][20] and lead to a lower carrier channel mobility. 21,22 Moreover, the charge exchange between the semiconductor and interface states or gate oxide states can lead to noise in the drain current ("1/f noise") 23,24 and shifts in threshold voltage (bias temperature instability).…”