Investigation of annealed, thin(∼2.6 nm)-Al₂O₃/AlGaN/GaN metal-insulator-semiconductor heterostructures on Si(111) via capacitance-voltage and current-voltage studies

Abstract

Investigation of annealed, thin(~ 2.6 nm)-Al₂O₃/AlGaN/GaN metal-insulatorsemiconductor heterostructures on Si(111) via capacitance-voltage and current-voltage studies Annealed, thin(~ 2.6 nm)-Al2O3/AlGaN/GaN metal-insulator-semiconductor (MIS) heterostructures on Si(111) are fabricated and studied via capacitance-voltage (C-V) measurements to quantify densities of fast and slow interface trap states and via current-voltage (I-V) measurements to investigate dominant gate current leakage mechanisms. Dual-sweep C-V measurements reveal small voltage hysteresis (~ 1 mV) around threshold voltage, indicating a low slow interface trap state density of ~ 10 9 cm -2 . Frequency-dependent conductance measurements show fast interface trap state density ranging from 8 × 10 12 to 5 × 10 11 eV -1 cm -2 at energies from 0.275 to 0.408 eV below the GaN conduction band edge. Temperature-dependent I-V characterizations reveal that trap-assistant tunneling (TAT) dominates the reverse-bias carrier transport while the electric field across the Al2O3 ranges from 3.69 to 4.34 MV/cm, and the dominant Al2O3 trap state energy responsible for such carrier transport is identified as 2.13 ± 0.02 eV below the Al2O3 conduction band edge. X-ray photoelectron spectroscopy measurements on Al2O3 before and after annealing suggest an annealing-enabled reaction between Al-O bonds and inherent H atoms. Overall, we report that annealed, thin-Al2O3 dielectric is an effective (Al)GaN surface passivation alternative when minimizing passivation-

Quantitative analysis of electrically active defects in Au/AlGaN/GaN HEMTs structure using capacitance–frequency and DLTS measurements

“…However, at low frequencies, less shallow states also contribute to the trapping and de-trapping processes, which increases the capacitance. Hence, capacitance variations arise at different frequencies bowing to deep-level traps [10,11]. Therefore, we performed C-V measurements at different frequencies to determine the concentrations of net ionized impurities.…”

“…Therefore, it is important to characterize the electrical trap states in the HEMT structures. The frequencydependent capacitance and deep-level transient spectroscopy (DLTS) methods are sensitive techniques for investigating the following features: the position of the 2DEG channel; the density of the electrical trap states in the QW; and the relaxation times of the electrical trap states [7][8][9][10]. Usually, deep interface traps exist with long emission time constants in wide-bandgap semiconductors that do not follow the probing frequency; these traps generate excess capacitances and conductance, which cannot be explained using the traditional trapping mechanism [10][11][12].…”

“…The frequencydependent capacitance and deep-level transient spectroscopy (DLTS) methods are sensitive techniques for investigating the following features: the position of the 2DEG channel; the density of the electrical trap states in the QW; and the relaxation times of the electrical trap states [7][8][9][10]. Usually, deep interface traps exist with long emission time constants in wide-bandgap semiconductors that do not follow the probing frequency; these traps generate excess capacitances and conductance, which cannot be explained using the traditional trapping mechanism [10][11][12]. Therefore, frequency-dependent conductance methods have been widely used to evaluate the fast traps; current-voltage (I-V) measurements have also been used to evaluate the slow traps in AlGaN/ GaN structures.…”

Improved performance HEMT device with backup bulk for LNA application

“…(3)The type of structure backup bulk with two gates and two drains of electrodes, decrease the buffer leakage current, improves the carrier confinement, and reduces the SCEs [24][25][26].…”