Interface trap properties of thermally oxidized n-type 4H–SiC and 6H–SiC

Comparison of near-interface traps in Al2O3∕4H-SiC and Al2O3∕SiO2∕4H-SiC structures

“…In this context it should be emphasized that the prime objective of the present study is not to minimize the absolute values of D it but rather to compare the D it versus energy distribution for the Al 2 O 3 /4H-SiC and Al 2 O 3 /SiO 2 /4H-SiC capacitors. Figure 3 reveals clearly that the former ones are essentially free of electron traps for energies ≤0.2 eV below E c while the latter ones exhibit a high D it close to E c , in accordance with previous reports for the SiO 2 /4H-SiC interface [3,4,5,12]. On the other hand, the Al 2 O 3 /4H-SiC samples display a high density of deep states from ≈0.4 to ≈0.7 eV below E c and these are due to the traps with a thermally activated filling process, as discussed in conjunction with Fig.…”

“…In fact, the TDRC spectra in Fig. 2 and their dependence on charging voltage and charging temperature display close resemblance with that recently reported for SiO 2 /4H-SiC capacitors [12]. Hence, the properties of the Al 2 O 3 /SiO 2 /SiC capacitors appear to be dominated by the SiO 2 /SiC interface.…”

“…Hence, the properties of the Al 2 O 3 /SiO 2 /SiC capacitors appear to be dominated by the SiO 2 /SiC interface. Rudenko et al [12] have argued that both groups of traps are due to the same type of intrinsic interfacial defect of acceptor character with a spatial distribution extending from the interface into an oxycarbide transition region. The 70 K peak is assigned to communication of the defect trap with the SiC conduction band edge while the broad peak at ≈140 K is ascribed to communication with the conduction band edge of the oxycarbide transition layer, exhibiting a gradually increasing offset ranging from the conduction band edge of 4H-SiC to that of SiO 2 .…”

Tailoring Oxide/Silicon Carbide Interfaces: NO Annealing and Beyond

“…The dominant defects however, are likely oxide-related. Indeed, Si-Si bonds of various lengths can extend into SiO 2 yielding interface and border traps [6,17,50,72,92,112]. As mentioned before, the majority of corresponding bonding and antibonding states are located outside of the silicon gap but the former induce a distribution centered between the 4H and 6H-SiC conduction bands.…”

Spatial Localization of Carrier Traps in 4H-SiC MOSFET Devices Using Thermally Stimulated Current

“…10 Previous reports of TSC measurements on SiC have focused on metal-oxide-semiconductor (MOS) capacitors fabricated on n-and p-type 4H-and 6H-epitaxial layers. [11][12][13][14] Studies of p-type 6H-SiC MOS capacitors by Lysenko et al 11 and Ó lafsson et al 12 showed two main peaks in the TSC spectra, located at approximately 50 K and 70 K. The origin of the former peak was attributed to interface states, whereas the latter was concluded to be due to Al acceptors (E A = 160 meV to 230 meV). [15][16][17] On n-type 4H-SiC, Rudenko et al observed TSC peaks near 40 K, 90 K, and 150 K. 13,14 The 40-K peak was attributed to N donor ionization, and the other two peaks were due to the presence of interface states near the conduction band.…”