Carrier transport properties in inversion layer of Si-face 4H–SiC MOSFET with nitrided oxide

Abstract

We propose a method to evaluate the carrier transport properties in the inversion layer of 4H-SiC metal-oxide-semiconductor field-effect transistors (MOSFETs) experimentally. Our approach differs from conventional methods, which have adjusted the parameters in conventional mobility models. Intrinsic phonon-limited mobility (μ phonon ) in the SiC MOSFET was observed by suppressing the severe impact of Coulomb scattering on the SiC MOS inversion layer by lowering the acceptor concentration (N A ) of the p-type well region to the order of 10 14 cm −3 . In this study, we investigated the carrier transport properties in the inversion layer of Si-face 4H-SiC MOSFETs with nitrided oxide. It is revealed that the μ phonon of the SiC MOSFET is a quarter or less than the conventionally presumed values. Additionally, surface roughness scattering is found not to be the most dominant mobility-limiting factor even at high effective normal field (E eff ) for the SiC MOSFET. These results demonstrate that conventional understanding of carrier scattering in the SiC MOS inversion layer should be modified, especially in the high E eff region.

Dipole Scattering at the Interface: The Origin of Low Mobility observed in SiC MOSFETs

“…The temperature dependence of µ phdp in the case of a low-doped P-well and a medium-doped P-well is limited. The observed temperature dependence of µ phdp qualitatively agrees with previous experimental results [11,15,27].…”

“…The second cause is the low free electron mobility (µ free ) of the remaining mobile electrons in the MOS channel [8,9,[11][12][13][14][15][16]. It has been found that the high density of D it near E C can be reduced and thus the n free s can be improved [8][9][10].…”

“…Owing to its technological importance, a number of detailed experimental studies on the µ free have been undertaken using Hall effect measurements [11][12][13][14][15][16]. We note that the experimental results regarding the mobility in MOSFETs are generally parameterized bt the Effective field (E eff ) in order to investigate the mobility-limiting scattering mechanisms [20][21][22][23].…”

“…The µ ph shows a rapid increase as the temperature decreases. Experimentally obtained observations of temperature dependence of the mobility at low temperatures are limited [11,15,27].…”

Determination of the interface between amorphous insulator and crystalline 4H–SiC in transmission electron microscope image by using convolutional neural network

“…The roughness at the interface is a possible cause of the low interface conductivity of SiC MOSFETs [2][3][4][5]. The surface-roughness-scattering model established for SiO2/Si interfaces [6][7][8][9][10] has been partially used to analyze the mobility at SiO2/4H-SiC interfaces [11][12][13][14]. For SiO2/Si interfaces, the power spectral density of surface roughness was extracted from the boundary line between the two phases in the cross-sectional image obtained by a transmission electron microscope (TEM) [9], and mobility was calculated from the theoretical formula [6][7][8] and power spectral density.…”