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

Abstract

The reason for the effective removal of interface traps in SiO 2 /4H-SiC (0001) structures by boron (B) incorporation was investigated by employing lowtemperature electrical measurements. Low-temperature capacitance-voltage and thermal dielectric relaxation current measurements revealed that the density of electrons captured in slow interface traps in B-incorporated oxide is lower than that in dry and NO-annealed oxides. These results suggest that near-interface traps can be removed by B incorporation, which is considered to be an important reason for the increase in the field-effect mobility of 4H-SiC metal-oxide-semiconductor devices. A model for the passivation mechanism is proposed that takes account of stress relaxation during thermal oxidation.

Bias temperature instability in SiC metal oxide semiconductor devices

“…Sequential C-V measurements with an increased initial gate voltage are used to evaluate the stability of MOS devices and measure NIOTs [64,99,100]. Moghadam et al [64] conducted sequential C-V measurements at 10 kHz to identify the density of NIOTs in n-type MOS capacitors.…”

Introductory Chapter: Need of SiC Devices in Power Electronics - A Beginning of New Era in Power Industry

“…In case of Si, the inversion channel mobility can be as much as 50% of bulk mobility [29]. In addition to standard N 2 O annealing, there are different types of annealing which can increase the channel mobility significantly, but these annealings degrade some important parameters of a MOSFET and hence cannot be used [44][45][46][47][48][49][50]. More work is still needed in this field to improve the performance of SiC MOSFETs.…”

Boron and barium incorporation at the 4H-SiC/SiO2 interface using a laser multi-charged ion source

“…This causes power losses and reduces device switching speed. In addition to NO anneal, there has been several reports that performed interface treatments using hydrogen [4], phosphorus [5], sodium [6], antimony [7], boron [8], alkali (Rb and Cs), and alkali earth (Ca, Sr, and Ba) interface layers [9]. These treatments were performed individually.…”

“…Phosphorous increased the channel mobility to ~80 cm 2 /Vs but appeared to have a thermodynamic driving force to diffuse throughout the SiO2 forming a phosphosilicate glass, which results in degraded dielectric properties [5]. Boron has been shown to improve the mobility greatly by passivating the interface traps [8]. Boron may also be effective in reducing the interfacial stress, and thus in reducing the trap density, because B2O3 is known to be a network former that reduces the network connectivity of SiO2 [11].…”