Low onset voltage of GaN on Si Schottky barrier diode using various recess depths (original) (raw)
Related papers
IEEE Transactions on Electron Devices, 2016
In this paper, a further leakage reduction of AlGaN/GaN Schottky barrier diodes with gated edge termination (GET-SBDs) has been achieved by optimizing the physical vapor deposited TiN as the anode metal without severe degradation of ON-state characteristics. The optimized GET-SBD multifinger power diodes with 10 mm anode width deliver ∼4 A at 2 V and show a median leakage of 1.3 µA at 25°C and 3.8 µA at 150°C measured at a reverse voltage of −200 V. The temperature-dependent leakage of Si, SiC, and our GaN power diodes has been compared. The breakdown voltage (BV) of GET-SBDs was evaluated by the variation of anode-to-cathode spacing (L AC) and the length of field plate. We observed a saturated BV of ∼600 V for the GET-SBDs with L AC larger than 5 µm. The GET-SBD breakdown mechanism is shown to be determined by the parasitic vertical leakage current through the 2.8 µm-thick buffer layers measured with a grounding substrate. Furthermore, we show that the forward voltage of GET-SBDs can be improved by shrinking the lateral dimension of the edge termination due to reduced series resistance. The leakage current shows no dependence on the layout dimension L G (from 2 to 0.75 µm) and remains at a value of ∼10 nA/mm. The optimized Au-free GET-SBD with low leakage current and improved forward voltage competes with high-performance lateral AlGaN/GaN SBDs reported in the literature.
High-Performance AlGaN/GaN Schottky Diodes With an AlGaN/AlN Buffer Layer
IEEE Electron Device Letters, 2000
High-performance AlGaN/GaN Schottky barrier diodes are fabricated on a composite AlGaN/AlN buffer layer with low screw-type and high edge-type dislocation densities. Without edge termination, the devices with 30-µm anode-to-cathode spacing exhibit a high breakdown voltage (V B) of 3489 V, a low leakage current (I R) of less than 0.2 µA at −2000 V, and a low specific on-resistance (R on) of 7.9 mΩ • cm 2 , resulting in a figure of merit (V 2 B /R on) as high as 1.54 GW/cm 2. Their switching characteristics as revealed by the reverse-recovery transient waveform exhibit a short reverse-recovery time of 17 ns.
ECS Journal of Solid State Science and Technology, 2017
In this work, low turn-on voltage (V on), low leakage current (I R) and high breakdown voltage (V BR) AlGaN/GaN Schottky barrier diodes (SBDs) are fabricated on 6-inch Silicon substrates using an anode recess process combined with SF 6 plasma treatment. Using this process, turn-on voltage is reduced from 1.3 V to 0.6 V, compared to the planar untreated devices due to the reduction of Schottky barrier height by having the Schottky metal in contact with the two dimensional electron gas at the AlGaN/GaN interface. Meanwhile, the V BR is increased from 400 V to 455 V due to the presence of plasma implanted fluorine ions near the anode. This process also results in a smaller device capacitance, which leads to the reduction of reverse recovery time from 12.9∼14.4 ns to 9.6∼10.7 ns.
Influence of contact shape on AlGaN/GaN Schottky diode prepared on Si with thick buffer layer
Applied Physics A, 2013
A report on the fabrication and characterization of high performance conventional and ring-shaped AlGaN/ GaN Schottky barrier diode on Si is presented. The resulting device exhibited low leakage current, which led to a detectivity performance of 3.48 × 10 13 and 1.76 × 10 13 cm Hz 1/2 W −1 , respectively, for both conventional and ring-shaped Schottky diode. The differential resistances of both devices were obtained at approximately 1.37 × 10 12 and 1.41 × 10 13 , respectively. The zero bias peak responsivities of conventional and ring-shaped Schottky diodes were estimated to be 3.18 and 2.08 A cm −2 /W, respectively. The typical UV to visible rejection ratio was observed over three orders of magnitude at zero bias. The C-V measurements was used to calculate and analyze the polarization sheet charge density of the AlGaN barrier layer by using self-consistently solving Schrodinger's and Poisson's equations. It is demonstrated that the ring shape of the Schottky barrier has higher polarization sheet charge density, which has the consequence that the Schottky shape has influence on the strain of the AlGaN barrier layer.
Barrier Height Variation in Ni-Based AlGaN/GaN Schottky Diodes
IEEE Transactions on Electron Devices, 2017
In this paper, we have investigated Ni-based AlGaN/GaN Schottky diodes comprising capping layers with silicon-technology-compatible metals such as TiN, TiW, TiWN, and combinations thereof. The observed change in Schottky barrier height of a Ni and Ni/TiW/TiWN/TiW contact can be explained by stress effects induced by the TiW/TiWN/TiW capping layer, rather than by chemical reactions at the metal-semiconductor interface. Secondary-ion mass spectroscopy and transmission electron microscopy techniques, for samples with and without a TiW/TiWN/TiW cap, have been used to show that no chemical reactions take place. In addition, electrical characterization of dedicated samples revealed that the barrier height of Ni/ TiW/TiWN/TiW contacts increases after stepwise selective removal of the TiW/TiWN/TiW cap, thus demonstrating the impact of strain.
A 600 V AlGaN/GaN Schottky barrier diode on silicon substrate with fast reverse recovery time
physica status solidi (c), 2012
Lateral AlGaN/GaN Schottky barrier diodes on silicon (111) substrate have been fabricated and characterized. The Hall measurement shows the mobility of 1430 cm 2 /V-s with a sheet carrier density of 9.8 × 10 12 cm-2 for the AlGaN/GaN structure. The specific on-state resistance (R on) is 1.27 mΩ-cm 2 , while the forward turn-on voltage is 1.43 V at the current density of 100 A/cm 2 for device with Schottky-to-ohmic distance of 10 μm. The measured reverse breakdown voltage (V B) at room temperature is up to 600 V without edge termination. The figure-of-merit, (V B) 2 /R on , is 302.7 MWcm-2 , and fast reverse recovery time is observed for device switched from a forward current density of 720 A/cm 2 to a reverse bias of 30 V with di/dt of 60 A/μs.
Microelectronic Engineering, 2007
In this paper, we report the breakdown voltage (BV) of AlGaN/GaN based Schottky diodes with field plate edge termination. Simulation and fabrication of AlGaN/GaN Schottky diodes were carried out. The simulations were performed using the commercial 2-D device simulator DESSIS. From the simulations, it is found that for a given gate-Ohmic distance (L gd) of 10 lm, 2DEG of 1 • 10 13 cm À2 and field plate length (L FP) of 2.5 lm, highest BV can be obtained for a silicon nitride thickness of 8000 Å and this BV value is more than 5 times that for a Schottky diode without field plate. The breakdown voltages were also simulated for different field plate lengths. The BV values obtained on the fabricated Schottky diodes are compared with the simulation data and the experimental results follow the trend obtained from the simulation. Simulations were also carried out on a Schottky diode with field plate placed over a stepped insulator with L gd = 10 lm, L FP = 5 lm and 2DEG = 1 • 10 13 cm À2 and the obtained BV values are about 7 times that without field plate.
Modeling and Characterization of Vertical GaN Schottky Diodes With AlGaN Cap Layers
IEEE Transactions on Electron Devices, 2017
A new GaN Schottky device structure suitable for power electronic applications is discussed. A GaN Schottky diode with an ultrathin AlGaN cap layer was fabricated using a Ni/Au metal stack as the Schottky electrode. CV measurements at various temperatures were used to calculate a barrier height of 0.65 V with a free electron concentration of 5×10 15 cm −3 both of which appear temperature independent. A forward conduction model based on a thermionic emission-diffusion process with tunneling through the AlGaN barrier was developed and compared favorably to experimental data. A reverse conduction model utilizing thermionic field emission with a triangular energy barrier is presented and then improved upon with a scaling factor that modifies the barrier thickness. This thermionic field emission model compares more favorably with the experimental data than the standard thermionic emission model typically used in Schottky diodes. Both the forward conduction and reverse conduction characteristics were assessed at room temperature and elevated temperature. The model can be used to predict how the physical parameters of the device affect its IV characteristics.
Japanese Journal of Applied Physics, 2006
We have proposed and fabricated a lateral GaN Schottky barrier diode (SBD) that increases the breakdown voltage and decreases the leakage current by the oxidation of a Ni/Au Schottky contact. After an oxidation, the anode current was increased under a high anode bias, whereas the turn-on voltage was slightly increased. The leakage current was considerably decreased to less than 1 nA after the oxidations of 5 and 10 min. A high breakdown voltage of 750 V was measured in the proposed GaN SBD when multiple floating metal rings (FMRs) were used for edge termination and oxidation was employed. We have also measured the reverse recovery waveforms at room temperature and 125 C and the fabricated GaN SBDs show very fast reverse recovery characteristics.