共查询到20条相似文献,搜索用时 140 毫秒
1.
Zhan A.P. Dang G.T. Fan Ren Hyun Cho Kyu-Pil Lee Pearton S.J. Jenn-Inn Chyi Nee T.-Y. Chuo C.-C. 《Electron Devices, IEEE Transactions on》2001,48(3):407-411
The performance of GaN p-i-n and Schottky rectifiers fabricated on the same wafer was investigated as a function of device size and operating temperature. There was a significant difference in reverse breakdown voltage (490 V for p-i-n diodes; 347 V for the Schottky diodes) and forward turn-on voltage (~5 V for the p-i-n diodes; ~3.5 V for the Schottky diodes). Both types of device showed a negative temperature coefficient for reverse breakdown, with value -0.34±0.05 V·K-1 相似文献
2.
Masayoshi Umeno Takashi Egawa Hiroyasu Ishikawa 《Materials Science in Semiconductor Processing》2001,4(6)
A recessed gate AlGaN/GaN high-electron mobility transistor (HEMT) on sapphire (0 0 0 1), a GaN metal-semiconductor field-effect transistor (MESFET) and an InGaN multiple-quantum well green light-emitting diode (LED) on Si (1 1 1) substrates have been grown by metalorganic chemical vapor deposition. The AlGaN/GaN intermediate layers have been used for the growth of GaN MESFET and LED on Si substrates. A two-dimensional electron gas mobility as high as 9260 cm2/V s with a sheet carrier density of 4.8×1012 cm−2 was measured at 4.6 K for the AlGaN/GaN heterostructure on the sapphire substrate. The recessed gate device on sapphire showed a maximum extrinsic transconductance of 146 mS/mm and a drain–source current of 900 mA/mm for the AlGaN/GaN HEMT with a gate length of 2.1 μm at 25°C. The GaN MESFET on Si showed a maximum extrinsic transconductance of 25 mS/mm and a drain–source current of 169 mA/mm with a complete pinch-off for the 2.5-μm-gate length. The LED on Si exhibited an operating voltage of 18 V, a series resistance of 300 Ω, an optical output power of 10 μW and a peak emission wavelength of 505 nm with a full-width at half-maximum of 33 nm at 20 mA drive current. 相似文献
3.
R. P. Tompkins J. R. Smith K. W. Kirchner K. A. Jones J. H. Leach K. Udwary E. Preble P. Suvarna J.M. Leathersich F. Shahedipour-Sandvik 《Journal of Electronic Materials》2014,43(4):850-856
We have examined the performance of gallium nitride (GaN) high-power Schottky diodes fabricated on unintentionally doped (UID) metalorganic chemical vapor deposition (MOCVD) films grown simultaneously on four substrates ranging in threading dislocation density from 5 × 103 cm - 2 to 1010 cm - 2. The substrates were an intentionally doped and a UID freestanding hydride vapor phase epitaxy substrate, an MOCVD GaN template grown on a sapphire wafer, and a bulk GaN substrate grown via an ammonothermal method. Capacitance–voltage (C–V) results showed the carrier concentration was ~2 × 1016 cm?3 for films grown on each of the four substrates. With that doping level, the theoretical breakdown voltage (V b) is ~1600 V. However, measured V b for the devices tested on each of the four substrates fell short of this value. Also, the breakdown voltages across each of the four substrates were not substantially different. This result was especially surprising for films grown on bulk GaN substrates, because of their superior crystal quality, as determined from their x-ray rocking curve widths. Simple probability calculations showed that most of the diodes tested on the bulk substrate did not cover a single threading dislocation. Although optimization of edge-termination schemes is likely to improve V b, we believe that point defects, not threading dislocations, are the main reason for the reduced performance of these devices. 相似文献
4.
Shelton B.S. Ting Gang Zhu Lambert D.J.H. Dupuis R.D. 《Electron Devices, IEEE Transactions on》2001,48(8):1498-1502
The use of GaN for the fabrication of Schottky and p-i-n rectifiers presents an opportunity to take advantage of the high-voltage and high-power handling characteristics of the III-nitride materials. We report the results of two-dimensional (2-D) device simulations to provide estimates of the performance limitations and a comparison for vertical- and horizontal-geometry GaN mesa and planar Schottky-barrier rectifiers and p-i-n devices. The simulated performance of devices with practical drift region thicknesses indicate that it is possible to realize Schottky-barrier and p-i-n rectifiers with turn-on voltages of V 0N<5 V, and blocking voltages of up to VBR=-2,320 V and -675 V, and figure of merit values of VBR2/R0N>1000 and 3000 MW/cm2 , respectively 相似文献
5.
Comparison of current-voltage characteristics of n- and p-type 6H-SiC Schottky diodes 总被引:2,自引:0,他引:2
Q. Zhang V. Madangarli M. Tarplee T. S. Sudarshan 《Journal of Electronic Materials》2001,30(3):196-201
Current-voltage (I–V) characteristics of n- and p-type 6H−SiC Schottky diodes are compared in a temperature range of room
temperature to 400°C. While the room temperature I–V characteristics of the n-type Schottky diode after turn-on is more or
less linear up to ∼100 A/cm2, the I–V characteristics of the p-type Schottky diode shows a non-linear behavior even after turn-on, indicating a variation
in the on-state resistance with increase in forward current. For the first time it is shown that at high current densities
(>125 A/cm2) the forward voltage drop across p-type Schottky diodes is lower than that across n-type Schottky diodes on 6H−SiC. High
temperature measurements indicate that while the on-state resistance of n-type Schottky diodes increases with increase in
temperature, the on-state resistance of p-type Schottky diodes decreases with increase in temperature up to ∼330 K. 相似文献
6.
Design of edge termination for GaN power Schottky diodes 总被引:1,自引:0,他引:1
J. R. Laroche F. Ren K. W. Baik S. J. Pearton B. S. Shelton B. Peres 《Journal of Electronic Materials》2005,34(4):370-374
The GaN Schottky diodes capable of operating in the 300–700-V range with low turn-on voltage (0.7 V) and forward conduction
currents of at least 10 A at 1.4 V (with corresponding forward current density of 500 A/cm2) are attractive for applications ranging from power distribution in electric/hybrid electric vehicles to power management
in spacecraft and geothermal, deep-well drilling telemetry. A key requirement is the need for edge-termination design to prevent
premature breakdown because of field crowding at the edge of the depletion region. We describe the simulation of structures
incorporating various kinds of edge termination, including dielectric overlap and ion-implanted guard rings. Dielectric overlap
using 5-μm termination of 0.1–0.2-μm-thick SiO2 increases the breakdown voltage of quasi-vertical diodes with 3-μm GaN epi thickness by a factor of ∼2.7. The use of even
one p-type guard ring produces about the same benefit as the optimized dielectric overlap termination. 相似文献
7.
Yi Zhou Dake Wang Claude Ahyi Chin-Che Tin John Williams Minseo Park N. Mark Williams Andrew Hanser 《Solid-state electronics》2006,50(11-12):1744-1747
Vertical Schottky rectifiers have been fabricated on a free-standing n-GaN substrate. Circular Pt Schottky contacts with different diameters (50 μm, 150 μm and 300 μm) were prepared on the Ga-face and full backside ohmic contact was prepared on the N-face by using Ti/Al. The electron concentration of the substrate was as low as 7 × 1015 cm−3. Without epitaxial layer and edge termination scheme, the reverse breakdown voltages (VB) as high as 630 V and 600 V were achieved for 50 μm and 150 μm diameter rectifiers, respectively. For larger diameter (300 μm) rectifiers, VB dropped to 260 V. The forward turn-on voltage (VF) for the 50 μm diameter rectifiers was 1.2 V at the current density of 100 A/cm2, and the on-state resistance (Ron) was 2.2 mΩ cm2, producing a figure-of-merit (VB)2/Ron of 180 MW cm−2. At 10 V bias, forward currents of 0.5 A and 0.8 A were obtained for 150 μm and 300 μm diameter rectifiers, respectively. The devices exhibited an ultrafast reverse recovery characteristics, with the reverse recovery time shorter than 20 ns. 相似文献
8.
Oliver Breitschädel Bertram Kuhn Ferdinand Scholz Heinz Schweizer 《Journal of Electronic Materials》1999,28(12):1420-1423
The backward current of Schottky contacts on unintentionally doped GaN samples prepared by different dry-etching methods was
investigated. It was found that an ion beam etching (IBE) process with an accelerating voltage of 250 V under an angle of
20 degrees to minimize channeling achieves the best results. The backward current in this case is 4 × 10−10 A/μm2 compared to the backward current of the unetched sample of 1 × 10−7 A/μm2 at −100 V. With this process, recessed gate HEMTs on AlGaN/GaN heterostructures grown by low pressure MOVPE were fabricated
and compared to HEMTs without recess. The applied gate recess etching technique improves the leakage current by nearly a factor
of two. The maximum transconductance is improved from 40 mS/mm to 60 mS/mm at a gate length of 4 μm. 相似文献
9.
K. Ohtsuka Y. Matsuno Y. Hase H. Sugimoto K. Fujihira Y. Tarui M. Imaizumi T. Takami T. Ozeki 《Materials Science in Semiconductor Processing》2003,6(5-6):359-362
Ti/4H–SiC Schottky barrier diode without any intentional edge termination is fabricated. The obtained properties, low on-resistance of 3 mΩ cm2 and low leakage current of 10−4 A/cm2 at 1000 V, are evaluated by device simulation considering pinning at metal/semiconductor interface. The breakdown voltage is explained by minimization of electric field enhancement at the Schottky electrode edge due to pinning. The leakage current corresponds to Schottky barrier tunneling current depending on drift layer doping and Schottky barrier height. 相似文献
10.
Au/n-GaN Schottky diodes with the Au electrode deposited at low temperature (LT=77K) have been studied. In comparison, the
same chip of GaN epitaxial layer was also used for room temperature Schottky diodes. The low temperature Schottky diodes exhibit
excellent performance. Leakage current density as low as 2.55×10−11 A·cm−2 at −2.5 V was obtained in the LT Schottky diodes. The linear region in the current-voltage curve at forward bias extends
more than eight orders in current magnitude. Current-voltage-temperature measurements were carried out to study the characteristics
of the LT Schottky diodes. A typical barrier height of about 1.32 eV for the LT diode, which is the highest value ever reported,
was obtained. The obvious enhancement in electrical performance makes the LT processing a very promising technique for GaN
device application although the detailed mechanisms for the LT Au/n-GaN Schottky diodes are still under investigation. 相似文献
11.
A. Y. Polyakov N. B. Smirnov A. V. Govorkov A. P. Zhang F. Ren S. J. Pearton J. -I. Chyi T. -E. Nee C. -C. Chou C. -M. Lee 《Journal of Electronic Materials》2001,30(3):147-155
GaN p-i-n rectifiers with 4 μm thick i-layers show typical reverse breakdown voltages of 100–600 V. We have studied the temperature
dependence of current-voltage characteristics in these diodes, along with hole diffusion lengths and the deep level defects
present. Generally we find that i-layer background doping varies significantly (from <1014 cm−3 to 2–3×1016), which influences the current conduction mechanisms. The hole diffusion lengths were in the range 0.6–0.8 μm, while deep
level concentrations were ∼1016 cm−3. 相似文献
12.
Johnson J.W. Zhang A.P. Wen-Ben Luo Fan Ren Pearton S.J. Park S.S. Park Y.J. Jenn-Inn Chyi 《Electron Devices, IEEE Transactions on》2002,49(1):32-36
Schottky rectifiers with implanted p+ guard ring edge termination fabricated on free-standing GaN substrates show reverse breakdown voltages up to 160 V in vertical geometry devices. The specific on-state resistance was in the range 1.7-3.0 Ω·cm 2, while the turn-on voltage was ~1.8 V. The switching performance was analyzed using the reverse recovery current transient waveform, producing an approximate high-injection, level hole lifetime of ~15 ns. The bulk GaN rectifiers show significant improvement in forward current density and on-state resistance over previous heteroepitaxial devices 相似文献
13.
GaInN/GaN solar cells made without p-type material are demonstrated using an oxidized Ni/Au Schottky barrier design to collect photo-generated carriers. The best devices exhibit a short-circuit current density of 0.065 mA/cm2 with an open-circuit voltage of 0.4 V under AM0 (1-Sun) illumination. Preliminary computer simulations are in reasonable agreement with experimental results, giving a pathway to improve device performance via iterative redesign and testing. 相似文献
14.
15.
W. S. Wong A. B. Wengrow Y. Cho A. Salleo N. J. Quitoriano N. W. Cheung T. Sands 《Journal of Electronic Materials》1999,28(12):1409-1413
Gallium nitride (GaN) thin films grown on sapphire substrates were successfully bonded and transferred onto GaAs, Si, and
polymer “receptor” substrates using a low-temperature Pd-In bond followed by a laser lift-off (LLO) process to remove the
sapphire growth substrate. The GaN/sapphire structures were joined to the receptor substrate by pressure bonding a Pd-In bilayer
coated GaN surface onto a Pd coated receptor substrate at a temperature of 200°C. X-ray diffraction showed that the intermetallic
compound PdIn3 had formed during the bonding process. LLO, using a single 600 mJ/cm2, 38 ns KrF (248 nm) excimer laser pulse directed through the transparent sapphire substrate, followed by a low-temperature
heat treatment, completed the transfer of the GaN onto the “receptor” substrate. Cross-sectional scanning electron microscopy
and x-ray rocking curves showed that the film quality did not degrade significantly during the bonding and LLO process. 相似文献
16.
利用波长为248nm的KrF准分子激光器进行了蓝宝石衬底GaN外延层剥离。对极薄的MOCVD生长的单层GaN外延膜(3μm)和InGaNLD外延膜(5μm)实现了大面积剥离。对剥离蓝宝石衬底背面抛光和未抛光外延片的不同特点作了比较,激光剥离所需的能量密度阈值分别约为200mJ/cm2和300mJ/cm2,优化结果表明,能量密度分别在400mJ/cm2和600mJ/cm2可实现稳定的剥离。同时对剥离后的InGaN多量子阱LD结构薄膜进行了解理,SEM观察显示获得的InGaNLD腔面平整光滑。基于这种技术可以获得无蓝宝石衬底的GaN基光电子和电子器件。 相似文献
17.
J. Senawiratne Y. Li M. Zhu Y. Xia W. Zhao T. Detchprohm A. Chatterjee J.L. Plawsky C. Wetzel 《Journal of Electronic Materials》2008,37(5):607-610
We present a junction temperature analysis of GaInN/GaN quantum well (QW) light-emitting diodes (LEDs) grown on sapphire and
bulk GaN substrate by micro-Raman spectroscopy. The temperature was measured up to a drive current of 250 mA (357 A/cm2). We find better cooling efficiency in dies grown on GaN substrates with a thermal resistance of 75 K/W. For dies on sapphire
substrates we find values as high as 425 K/W. Poor thermal performance in the latter is attributed to the low thermal conductivity
of the sapphire. Three-dimensional finite-element simulations show good agreement with the experimental results, validating
our thermal model for the design of better cooled structures. 相似文献
18.
Liang?Pang Hui-Chan?Seo Patrick?Chapman Ilesanmi?Adesida Kyekyoon ?Kim 《Journal of Electronic Materials》2010,39(5):499-503
Selective-area growth (SAG) based on plasma-assisted molecular-beam epitaxy (PAMBE) was shown to facilitate improvement of
Ohmic contacts and direct-current (DC) characteristics for GaN-based field-effect transistors (FETs) over the widely accepted
ion-implantation technique. Twofold improvements in breakdown voltage were also demonstrated for samples grown on both sapphire
and silicon substrates. An AlGaN/GaN high-electron-mobility transistor (HEMT) fabricated with PAMBE-SAG exhibited a low specific
contact resistivity of 5.86 × 10−7 Ω cm2, peak drain current of 420 mA/mm, and high breakdown voltage of 77 V. These results demonstrate that PAMBE-SAG is suited
to fabricating HEMTs for high-power applications. 相似文献
19.
Self-heating in high-power AlGaN-GaN HFETs 总被引:2,自引:0,他引:2
We compare self-heating effects in AlGaN-GaN heterostructure field effect transistors (HFETs) grown on sapphire and SiC substrates. Heat dissipation strongly affects the device characteristics soon after the application of the source-drain voltage (in less than 10-7 s). Our results show that in HFET's with the total epilayer thickness less than 1.5 μm, the thermal impedance, Θ is primarily determined by the substrate material and not by the material of the active layer. For our devices grown on 6H-SiC substrates, we measured Θ of approximately 2°C·mm/W, which was more than an order of magnitude smaller than Θ=25°C mm/W measured for similar AlGaN/GaN HFET's grown on sapphire. Our results demonstrate that AlGaN-GaN HFET's grown on SiC substrates combine advantages of superior electron transport properties in AlGaN/GaN heterostructures with excellent thermal properties of SiC, which should make these devices suitable for high-power electronic applications 相似文献
20.
Hasnain C. Takeuchi T. Schneider R. Song S. Twist R. Blomqvist M. Kocot C. Flory C. 《Electronics letters》2000,36(21):1779-1780
Continuous-wave operation of etched-facet InGaN/GaN multiquantum-well ridge-waveguide laser diodes grown by low pressure MOVPE on a sapphire substrate has been achieved on-wafer for >2 min at 15% above threshold. The threshold current density and voltage were 9.1 kA/cm2 and 7.6 V, respectively, at 15°C, and the lasing wavelength was 400.6 nm 相似文献