Electron capture and emission properties of interface states in thermally oxidized and NO-annealed SiO2/4H-SiC

Abstract

Postoxidation annealing in nitric oxide ͑NO͒ results in a significant reduction of electronic states at SiO 2 / 4H-SiC interfaces. Measurements of electron trapping dynamics at interface states in both thermally oxidized and NO annealed SiO 2 / 4H-SiC interfaces were performed using constant-capacitance deep level transient spectroscopy ͑CCDLTS͒ and double-CCDLTS. We show that the interface state density in as-oxidized samples consists of overlapping distributions of electron traps that have distinctly different capture cross sections. The dominant trap distributions, centered at E c − 0.24 eV with ϳ 7 ϫ 10 −19 cm 2 , and at E c − 0.46 eV with ϳ 4 ϫ 10 −17 cm 2 are passivated by NO annealing. The remaining interface states all have capture cross sections in the range 10 −19 −10 −21 cm 2 .

Characterization of very fast states in the vicinity of the conduction band edge at the SiO2/SiC interface by low temperature conductance measurements

“…This trend is not specific to the NI states and is also observed for other interface states. 12,[20][21][22] The capture cross section of the NI states is larger than that of the other interface states, even near the E C . At E C ÀE T ¼ 0.15 eV, for example, the capture cross section of the NI states is about 1 Â 10 À14 cm 2 , while that of the conventional interface states is 10 À20 -10 À18 cm 2 .…”

Thermal Oxidation of Silicon Carbide (SiC) – Experimentally Observed Facts

“…Since SiC is a compound material of Si and C atoms, that is why the role of C atoms during the thermal growth of SiO 2 has been observed to be very crucial. Several studies [7][8][9] confirm the presence of C species in the thermally grown oxide, which directly affect the interface as well as dielectric properties of metal-oxide-semiconductor structures [10]. For this reason, rigorous studies on electrical behavior of thermally grown SiO 2 on SiC play a fundamental role in the understanding and control of electrical characteristics of SiCbased devices.…”

Effect of boron incorporation on slow interface traps in SiO2/4H-SiC structures

“…The observed slow interface traps cannot be explained solely by the fast interface states that reside exactly at the interface, and it is necessary to take the existence of NITs into account [14,19]. It has also been shown that the electron capture cross-section of the interface traps varies by several orders of magnitude and the value is small near the conduction band edge [26,27]. This implies that the traps are located in the oxide near the interface, and the capture cross-section is small because of the distance from the interface.…”