A Parametric Technique for Trap Characterization in AlGaN/GaN HEMTs

Abstract

A new parametric and cost-effective technique is developed to decouple the mechanisms behind current degradation in AlGaN/GaN HEMTs under a normal device operation: self-heating and charge trapping. A unique approach that investigates charge trapping using both source (I S ) and drain (I D ) transient currents for the first time. Two types of charge trapping mechanisms are identified: (i) bulk charge trapping occurring on a time scale of less than 1 ms, followed by (ii) surface charge trapping with a time constant larger than a millisecond. Through monitoring the difference between I S and I D , a bulk charge trapping time constant is found to be independent of both drain (V DS ) and gate (V GS ) biases. Surface charge trapping is found to have a much greater impact on a slow degradation when compared to bulk trapping and self-heating. At a short timescale (< 1 ms), the RF performance is mainly restricted by both bulk charge trapping and self-heating effects. However, at a longer time (> 1 ms), the dynamic ON resistance degradation is predominantly limited by surface charge trapping.

A Novel AlGaN/Si3N4 Compound Buffer Layer HEMT with Improved Breakdown Performances

“…The SiN x passivation layer on the surface of the device is widely utilized to suppress the current collapse, and the interface states between the SiN x and AlGaN barrier layers have been broadly investigated [ 32 , 33 , 34 , 35 ]. The existence of donor-type traps between the interface has been demonstrated, and in the proposed BP-HEMT, donor-type traps are introduced correspondingly at the interface between the AlGaN buffer and Si 3 N 4 buried layer during fabrication.…”

“…The R on,sp also evidently indicates a good agreement between simulated and experimental data. A fixed acceptor trap concentration of 1 × 10 18 cm −3 and a fixed donor trap concentration of 1 × 10 13 cm −2 between the AlGaN barrier layer and passivation layer are equipped simultaneously [ 34 , 35 ]. The lateral dimensions and other doping characteristics of the devices are given in Table 1 .…”

Advancements in energy efficientGaNpower devices and power modules for electric vehicle applications: a review

“…A novel parametric technique is proposed that can decouple the charge trapping and selfheating mechanisms. 147 It is a cost-effective method in which the temperature effects are examined during the transient measurements. The JEDEC standards are well written for the Si MOSFETS.…”

Characterization of traps in GaN-based HEMTs by drain voltage transient and capacitance deep-level transient spectroscopy

“…Figure 3(a) presented the TCS of three electron traps identified from the voltage transient curves in figure 2(b). It revealed that the time constants of three traps were almost constant under different filling voltages, suggesting that the traps should be individual trap levels due to the unchanged charge trapping rate [8,33]. In addition, the absolute amplitudes of three traps identified with the DAS were shown in figure 3(b), which reflected the contribution of each trap to the transient variation exactly [22].…”

“…GaN-based high-electron-mobility transistors (HEMTs) have demonstrated excellent performance in high power [1], high voltage [2], and high frequency applications [3] owing to the superior characteristics [4][5][6][7]. However, the traps existing in the barrier or buffer layer of the HEMTs significantly restrict the performance and long-term reliability of the device [8,9], * Author to whom any correspondence should be addressed. and the physical properties of these traps still require further investigation [10].…”