Relationship between channel mobility and interface state density in SiC metal–oxide–semiconductor field-effect transistor

Abstract

Temperature dependence of threshold voltage in n-channel SiC metal–oxide–semiconductor field-effect transistors (MOSFETs) was studied. Linear relation was observed between the threshold voltage shift when the temperature varies from −150 to 150 °C and the number of the interface states present within the energy range of 0.2–0.4 eV from the conduction band edge energy Ec. This relationship revealed that the interface state profile near Ec in n-channel SiC MOSFETs can be represented by that in n-type SiC MOS capacitors. The relationship between the channel mobility and the interface state profile also suggested that the interface states within the energy range of 0.2–0.4 eV from Ec have little influence on the channel mobility.

Improved Channel Mobility in 4H-SiC MOSFETs by Boron Passivation

“…However, the channel mobility of 4H-SiC metaloxide-semiconductor field-effect transistors (MOSFETs) fabricated by standard dry oxidation is extremely low, thus hindering the development of SiC power MOSFETs. In particular, the channel mobility of the MOSFETs on the (0001) Si-face of 4H-SiC is extremely low, and typically below 10 cm 2 /Vs [1]. The low channel mobility is attributed to the high interface state density (D it ) near the conduction band edge of 4H-SiC [1].…”

“…In particular, the channel mobility of the MOSFETs on the (0001) Si-face of 4H-SiC is extremely low, and typically below 10 cm 2 /Vs [1]. The low channel mobility is attributed to the high interface state density (D it ) near the conduction band edge of 4H-SiC [1]. Various passivation methods such as nitridation of the interface with NO or N 2 O [2]- [6], Na-enhanced oxidation [7], [8], P diffusion into the gate oxide [9]- [12] have been proposed as ways of reducing D it and enhancing channel mobility.…”

Effect of gate oxidation method on electrical properties of metal-oxide-semiconductor field-effect transistors fabricated on 4H-SiC C(0001̄) face

“…These verified that pyrogenic gate oxidation increases hydrogen density at the SiO 2 /SiC interface compared to dry gate oxidation, and that the pyrogenic gate oxidation followed by H 2 POA increases considerably it. 5,11,12,18 Hence, it was expected that the MOSFETs fabricated on the C(0001) face can operate with-out the channel doping if it is fabricated under the gate oxidation condition in which the D it at the shallow level is low. The peak value of FE for SiC MOSFETs fabricated by pyrogenic gate oxidation followed by H 2 POA is 111 cm 2 /V s, which is much higher than that of SiC MOSFETs fabricated on a Si͑0001͒ face.…”

Theory of surface noise under Coulomb correlations between carriers and surface states

“…We list in Table I the characteristic density of traps N t0 estimated for typical conducting channels made of materials used in traditional, as well as advanced, semiconductor heterostructure technologies. 10,22,23 The results of these estimations indicate that for channels with the electron density ϳ10 11 cm Ϫ2 , the corresponding density of traps N t0 is of the same order of magnitude. For lower electron density in the channel, we obtain N t0 ϽN, while with increasing N, the opposite condition N t0 ϾN holds.…”