Impact of acceptor concentration on electrical properties and density of interface states of 4H-SiC n-metal-oxide-semiconductor field effect transistors studied by Hall effect

Abstract

Silicon carbide n-type metal-oxide-semiconductor field effect transistors (MOSFETs) with different p-body acceptor concentrations were characterized by Hall effect. Normally OFF MOSFETs with good transfer characteristics and low threshold voltage were obtained with a peak mobility of ∼145 cm2 V−1 s−1 for the lowest acceptor concentration. The results are explained in terms of an increase of Coulomb scattering centers when increasing the background doping. These scattering centers are associated to fixed oxide and trapped interface charges. Additionally, the observed mobility improvement is not related to a decrease of the interface states density as a function of background doping

Characterization of traps at nitrided SiO2/SiC interfaces near the conduction band edge by using Hall effect measurements

“…11) The core idea of the new characterization method of D it (E) near E C is to focus on the quantitative characterization of the densities of free (mobile) and trapped carriers at SiO 2 =SiC interfaces. [12][13][14][15][16][17][18] The physics governing the trapping of electrons at the interface is included in these two characterized quantities. However, to extract quantitative information on D it (E) from them, a careful examination of the relationship between the applied gate voltage (V g ) and the energy of the traps at the interface (E t ) is required.…”

Retrograde p-Well for 10-kV Class SiC IGBTs

“…Channel mobilities increased from 12 to 26cm 2 •V -1 •s -1 , and 61 to 78cm 2 •V -1 •s -1 on the Si 0001 and 11̅ 21 faces, respectively, when the acceptor doping concentration of p-body decreased from 2×10 17 to 1×10 16 cm -3 [36]. Of particular interest is the channel mobility of 145cm 2 •V -1 •s -1 obtained by Ortiz et al using a very low acceptor concentration of 1×10 15 cm -3 on the 0001 Si-face [37]. Previously, Katakami et al showed an improvement in the channel mobility of pchannel SiC IGBT using the combination of adopting an n-type base layer with a retrograde doping profile and additional wet re-oxidation annealing (wet-ROA) at 1100°C in the gate oxidation process.…”

Selective Doping in Silicon Carbide Power Devices

“…The impact of the p-type doping concentration of the body region on the MOSFET mobility is shown in Figure 7 b. In particular, the figure reports the behavior of the field effect mobility (determined in lateral MOSFETs) [ 70 ] and of the Hall mobility (determined by Hall bars) [ 74 ] for different values of the p-type doping. As can be seen, the mobility decreases with increasing doping concentration, which is due to the increase of the electric field in the channel region.…”

“…As can be seen, the mobility decreases with increasing doping concentration, which is due to the increase of the electric field in the channel region. As a consequence, a trade-off between the channel mobility and the threshold voltage is observed in 4H-SiC MOSFETs [ 68 , 74 ].…”

“…( b ) Field effect mobility and Hall mobility values determined in 4H-SiC MOSFET structures as a function of the p-body doping concentration. The data are taken from [ 70 , 74 ].…”