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Measurements of the near-interface oxide traps (NIOTs) aligned to the conduction band of silicon-carbide (SiC) are of particular importance as these active defects are responsible for degradation of the channel-carrier mobility in 4H-SiC MOSFETs. In this brief, a new method for measurement of the active NIOTs with energy levels aligned to the conduction band is proposed. The method utilizes transient-current measurements on 4H-SiC MOS capacitors biased in accumulation. Nitrided oxide and dry oxide are used to illustrate the applicability of the proposed measurement method. [ABSTRACT FROM AUTHOR]

This article presents the design and characterization of a direct current (dc) sensor utilizing the Hall effect in AlGaN/GaN 2-D electron gas (2DEG) four-terminal devices and a flux concentrator. The sensor was fabricated from an AlGaN/GaN/Si wafer grown by metal-organic chemical vapor deposition. The sensor exhibited excellent linearity and repeatability with a high Hall voltage under the primary current ranging from −5 to 5 A. The sensitivity of the sensor was measured to be 0.26 (V/A)/A at 20 °C and independent of ambient temperature up to 200 °C. The obtained result is greater than that of other reported Hall effect-based current sensors. The high sensitivity and thermal stability at varying temperatures are attributed to the high electron mobility, wide bandgap, and stability of carrier density in 2DEG. Combining these factors with the excellent mechanical strength, electrical conductivity, and chemical inertness of GaN, the proposed sensor is promising for current monitoring in a wide range of operation temperatures. [ABSTRACT FROM AUTHOR]

The parasitic capacitances of semiconductor power devices that contribute to the switching losses are voltage dependent, which can make calculations of their stored energy difficult. Typically, manufacturers will provide effective capacitance values to aid in circuit design and component selection. However, stored energy calculations using these effective capacitor values are erroneous. In this letter, we derive a new equation for the stored energy in the voltage-dependent capacitance associated with a semiconductor depletion region, such as in diodes and transistors. In particular, we show that the ½ term in ½ CV2 should be replaced by a new term γ, which depends on the device structure. By applying our proposed method to several commercial diodes and transistors, we show that it matches the measured data much better than using the effective capacitances. The proposed equation will enable better power circuit design by improving the accuracy of stored energy calculations. [ABSTRACT FROM AUTHOR]

Near-interface traps (NITs) with energy levels aligned to the conduction band and spatially located close to the SiO2/SiC interface are responsible for significant degradation of the channel-carrier mobility in 4H-SiC MOSFETs. In this paper, we investigate fast trapping and detrapping of the conduction-band electrons by NITs with energy levels localized between 0.13 and 0.23 eV above the bottom of the conduction band. The trapping and detrapping times were estimated to be in the range between the resolution limit of tens of nanoseconds and $1~\mu \text{s}$ by measuring the current through n-type MOS capacitors in response to a ramped voltage in the accumulation region. [ABSTRACT FROM AUTHOR]

The mobility of current carriers in the channel of FETs usually depends on the applied gate voltage. This paper presents experimental evidence that the electron mobility in the 2-D electron gas under the gate of AlGaN/GaN high-electron-mobility transistors (HEMTs) is actually independent of the gate voltage. This demonstration of the gate-voltage independence of the electron mobility relates to power HEMTs, and it was achieved by introducing a new method for the mobility measurement. The gate-voltage independence of the electron mobility was observed for a wide range of temperature, from 25 °C to 300 °C. Furthermore, it is confirmed that the HEMT mobility decreases with increased temperature according to the power law ( T^-k ) and with a quite high value of the power-law coefficient ( $k = 2.45$ ). [ABSTRACT FROM PUBLISHER]