Deep-Level Traps in AlGaN/GaN- and AlInN/GaN-Based HEMTs With Different Buffer Doping Technologies

Identification of Buffer and Surface Traps in Fe-Doped AlGaN/GaN HEMTs Using Y21 Frequency Dispersion Properties

“…Each DPO acquires the transients with different time windows over six decades, the first between 10 −8 s and 10 −2 s and the second between 10 −4 s and 10 2 s. These two acquisitions allow obtaining In the DCT experiment, the HEMT was initially biased at a trap-filling condition for a fixed time period of 100 ms to induce the carrier capture process in the device; then, the respective terminal voltage was changed to a de-trapping bias condition to observe the carrier emission phenomena. Note that the trap-filling pulse was applied either on the drain or gate of the transistor terminals (i.e., drain-lag or gate-lag filling pulse [2,7]), and the subsequent IDS transient recovery was measured over the time frame of 10 −6 s to 1 s. The DCT experiments were conducted for various operating temperatures ranging from 25 to 125 °C, which allowed us to calculate the trap activation energy (Ea) and capture the cross-section (σn) by using Arrhenius' law [16,22,25].…”

“…The carrier generation-recombination models such as SRH recombination statistics, Auger recombination, and radiative recombination model in the direct bandgap materials (GaN and AlGaN) are selected [31]. Note that the studied HEMT device was fabricated on the SiC substrate, and because of its high-thermal conductivity [2,6,7,16,30], the device's self-heating effects are less pronounced at lower bias voltages. From the experiments, the self-heating effects in the I DS -V DS and I DS -V GS properties were found to be minimal up to the drain voltage of V DS ≤ 10 V. In this work, the static I-V and Y-parameter simulations are carried out for V DS ≤ 10 V so that the thermal effects are not considered in the simulations.…”

“…Hence, the characterization of traps in the HEMT is essential for improving the epilayer crystalline quality. The drain current transient (DCT) spectroscopy [8][9][10][11][12][13][14][15][16][17][18] and low-frequency (LF) output-admittance (Y 22 ) parameters [15,16,[19][20][21][22][23][24][25][26][27] are the well-estimated techniques to characterize the deep-level defects present in the AlGaN/GaN HEMT structures.…”

“…Potier et al [22] applied LF Y 22 characterization to explore the trapping mechanism in the AlGaN/GaN and AlInN/GaN HEMTs. The 2D physics-based TCAD simulation studies are helpful to understand the physical phenomena involved in the LF dispersion due to the traps [7,16,25,29,30]. In our earlier works [7,16,25], it has been shown that the LF Y 22 experiments coupled with the simulation analysis are effective in identifying deep-level defects in the buffer region.…”

Characteristic Analysis of AlGaN/GaN HEMT with Composited Buffer Layer on High-Heat Dissipation Poly-AlN Substrates

“…Currently, the lattice mismatch in buffer layers is compensated with Fe and C doping, which causes the semi-insulating layer to increase the breakdown voltage and reduce the leakage current of the device. However, the Fe-doped buffer layer may have memory effects of the Fe diffusion associated with high growth temperatures [7][8][9], whereas severe current collapse can result from the trapping effects related to deep acceptors in the C-doped buffer layer [10][11][12]. In this study, a back-barrier (BB) layer was added to the buffer layer to reduce the influence of the doped acceptor between the channel and buffer layers.…”