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GaN HEMT器件经过钝化后,抑制电流崩塌效应明显,但同时产生其他负面效应,为了改善目前GaN HEMT钝化后漏电增加和击穿电压减小等情况,研究了钝化技术对GaN HEMT电流特性的影响,包括介质膜应力、折射率和表面预处理与器件饱和电流、电流崩塌量的关系,优化了表面预处理和钝化工艺条件.实验效果在CaN HEMT电特性上的改善明显.结果表明,采用折射率为2.1~2.2的SiN钝化膜,饱和电流密度增加到1 100 mA/mm,电流崩塌量小于10%,肖特基接触反向偏压为-20 V时泄漏电流达10-5A数量级. 相似文献
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提出了一种新型隐埋缓冲掺杂层(IBBD)高压SBD器件,对其工作特性进行了理论分析和模拟仿真验证。与常规高压SBD相比,该IBBD-SBD在衬底上方引入隐埋缓冲掺杂层,将反向击穿点从常规结构的PN结保护环区域转移到肖特基势垒区域,提升了反向静电释放(ESD)能力和抗反向浪涌能力,提高了器件的可靠性。与现有表面缓冲掺杂层(ISBD)高压SBD相比,该IBBD-SBD重新优化了漂移区的纵向电场分布形状,在保持反向击穿点发生在肖特基势垒区域的前提下,进一步降低反向漏电流、减小正向导通压降,从而降低了器件功耗。仿真结果表明,新器件的击穿电压为118 V。反向偏置电压为60 V时,与ISBD-SBD相比,该IBBD-SBD的漏电流降低了52.2%,正向导通电压更低。 相似文献
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利用一次离子注入同时形成有源区和结终端结构,实现3 300 V 4H-SiC肖特基二极管。器件的正向电压为1.7 V时,电流达到10.3 A,相应电流密度为100 A/cm2,比导通电阻为7.77 mΩ·cm2。在3 300 V反向偏置电压下反向漏电流为226μA。测试同一晶圆上的pn二极管显示,设计的场限环结终端击穿电压可以达到4 000 V,达到仿真结果的95%。分析发现肖特基二极管的漏电流主要由肖特基接触的热场电子发射产生,有源区的肖特基接触线宽直接影响器件的正向电流密度和反向漏电流。设计合适的肖特基接触宽度是实现高性能器件的关键。 相似文献
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利用一次离子注入同时形成有源区和结终端结构,实现3 300 V 4H-SiC肖特基二极管。器件的正向电压为1.7 V时,电流达到10.3 A,相应电流密度为100 A/cm2,比导通电阻为7.77 mΩ·cm2。在3 300 V反向偏置电压下反向漏电流为226μA。测试同一晶圆上的pn二极管显示,设计的场限环结终端击穿电压可以达到4 000 V,达到仿真结果的95%。分析发现肖特基二极管的漏电流主要由肖特基接触的热场电子发射产生,有源区的肖特基接触线宽直接影响器件的正向电流密度和反向漏电流。设计合适的肖特基接触宽度是实现高性能器件的关键。 相似文献
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高频功率AlGaN/GaN HEMT 的栅结构优化 总被引:2,自引:2,他引:0
本文研究了栅帽、栅源间距对AlGaN/GaN HEMT性能的影响。基于研究结果得出了优化高频功率AlGaN/GaN HEMT栅结构的方法。缩小栅场板可以有效提高器件的增益、截止频率(ft)、最大震荡频率(fmax)。通过减小栅场板长度,栅长0.35 器件的ft达到了30GHz、fmax达到了80GHz。采用tao型栅(栅帽偏向源侧)或者增加栅金属厚度还可以进一步优化 。缩小栅源的距离可以提高饱和漏电流和击穿电压,从而提高器件的输出功率。 相似文献
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设计了Ka波段GaN功率高电子迁移率晶体管(HEMT)外延材料及器件结构,采用AlN插入层提高了二维电子气(2DEG)浓度.采用场板结构提高了器件击穿电压.采用T型栅工艺实现了细栅制作,提高了器件高频输出功率增益.采用钝化工艺抑制了电流崩塌,提高了输出功率.采用通孔工艺减小源极寄生电阻,通过优化钝化层厚度减小了寄生电容,提高了器件增益.基于国产SiC外延材料及0.15 μm GaN HEMT工艺进行了器件流片,最终研制成功Ka波段GaN HEMT功率器件.对栅宽300 μm器件在29 GHz下进行了微波测试,工作栅源电压为-2.2V,源漏电压为20 V,输入功率为21 dBm时,器件输出功率为30 dBm,功率增益为9 dB,功率附加效率约为43%,功率密度达到3.3 W/mm. 相似文献
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MOS AlGaN/GaN HEMT研制与特性分析 总被引:1,自引:1,他引:0
研制出在蓝宅石衬底上制作的MOS AIGaN/GaN HEMT.器件栅长1um,源漏间距4um,采用电子束蒸发4nm的Si02做栅介质.在4V栅压下器件饱和电流达到718mA/mm,最大跨导为172mS/mm,ft和fmax分别为8.1和15.3GHz.MOS HEMT栅反向泄漏电流与未做介质层的肖特基栅相比,在反偏10V时由2.1×10-8mA/mm减小到8.3×10-9mA/mm,栅漏电流减小2个数量级.MOS AIGaN/GaN HEMT采用薄的栅介质层,在保证减小栅泄漏电流的同时未引起器件跨导明显下降. 相似文献
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D. Aurongzeb D.Y. Song G. Kipshidze B. Yavich L. Nyakiti R. Lee J. Chaudhuri H. Temkin M. Holtz 《Journal of Electronic Materials》2008,37(8):1076-1081
We report experiments on the formation of GaN nanowires on epitaxial GaN using thin layers of Ni. GaN covered with Ni shows
roughening that is strongly dependent on the thickness of the Ni layer and the annealing conditions. With the initial Ni thickness
of 0.8 nm we observe formation of Ni-filled antidots. These act as nucleation sites in the growth of GaN nanowires, allowing
for the preparation of nanowires with an average diameter as small as 30 nm. Dense and well-oriented nanowires are formed
by pulsed metallorganic chemical vapor deposition at 750°C. The size of the Ni features determines the diameter of the GaN
nanowires, resulting in good control over the formation process. 相似文献
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曲兰欣 《固体电子学研究与进展》1995,(2)
GaNMESFET宽带隙半导体已在高温电子学和大功率微波器件领域日益引起人们的重视。这主要是因为宽带隙材料产热率较低,击穿电场较高。GaN材料不仅具有这方面的特性,而且还可以制成异质结构的器件。据《Elec.Lett.》30卷第15期报道,S.C.B... 相似文献
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The electrical characteristics of gallium nitride (GaN) metal-oxide-semiconductor (MOS) capacitors and field-effect transistors
(FETs) made on as-grown surfaces, dry-etched surfaces using reactive-ion etching (RIE), and wet-etch treated surfaces after
the dry etch were measured. Capacitance and conductance techniques were used to obtain the MOS properties for capacitors.
Devices with only an RIE plasma dry-etch process have poor yield and noisy capacitance in the low-frequency accumulation region.
Those on dry/wet-etch treated samples have more negative ultraviolet (UV) assistant capacitance-voltage (CV) shift, and higher
interface-state densities than those on as-grown samples, but have similar surface potential fluctuation. Threshold voltages
of 2 V for an as-grown GaN MOSFET and 1 V for a dry/wet-etched MOSFET were measured. Maximum field-effect mobility for long-channel
(L
ch = 100 μm) MOSFETs on the as-grown GaN wafer and the dry/wet-etched GaN wafer were obtained as 167 cm2 V−1 s−1 and 119 cm2 V−1 s−1, respectively. The higher interface trap density and lower field-effect mobility indicate that post-plasma-etch wet etching
can only partially remove the damages from RIE. 相似文献
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Soohwan Jang F. Ren S. J. Pearton B. P. Gila M. Hlad C. R. Abernathy Hyucksoo Yang C. J. Pan Jenn-Inn Chyi P. Bove H. Lahreche J. Thuret 《Journal of Electronic Materials》2006,35(4):685-690
Si diffusion into GaN was studied as a function of encapsulant type (SiO2 or SiNx) and diffusion temperature. Using a SiO2 encapsulant, the Si diffusion exhibited an activation energy of 0.57 eV with a prefactor of 2.07×10−4 cm2 sec−1 in the temperature range 800–1,000°C. An enhancement-mode MgO/GaN-on-Si metal-oxide semiconductor field-effect transistor
(MOSFET) was fabricated utilizing Si-diffused regions under the source and drain to provide an accumulated channel. The gate
leakage through the undoped GaN was low enough for us to achieve good saturation behavior in the drain-current-voltage characteristics.
The devices showed improved transconductance and drain current relative to previous devices with Si-implanted source/drain
regions. 相似文献
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Growth of GaN on porous SiC and GaN substrates 总被引:1,自引:0,他引:1
C. K. Inoki T. S. Kuan C. D. Lee Ashutosh Sagar R. M. Feenstra D. D. Koleske D. J. Díaz P. W. Bohn I. Adesida 《Journal of Electronic Materials》2003,32(8):855-860
We have studied the growth of GaN on porous SiC and GaN substrates, employing both plasma-assisted molecular-beam epitaxy
(PAMBE) and metal-organic chemical-vapor deposition (MOCVD). For growth on porous SiC, transmission electron microscopy (TEM)
observations indicate that the epitaxial-GaN growth initiates primarily from surface areas between pores, and the exposed
surface pores tend to extend into GaN as open tubes and trap Ga droplets. The dislocation density in the GaN layers is similar
to, or slightly less than, that observed in layers grown on nonporous substrates. For the case of GaN growth on porous GaN,
the overgrown layer replicates the underlying dislocation structure (although considerable dislocation reduction can occur
as this overgrowth proceeds, independent of the presence of the porous layer). The GaN layers grown on a porous SiC substrate
were found to be mechanically more relaxed than those grown on nonporous substrates; electron-diffraction patterns indicate
that the former are free of misfit strain or are even in tension after cooling to room temperature. 相似文献
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I. K. Shmagin J. F. Muth R. M. Kolbas S. Krishnankutty S. Keller A. C. Abare L. A. Coldren U. K. Mishra S. P. Den Baars 《Journal of Electronic Materials》1997,26(3):325-329
Photoluminescence (PL) characteristics of GaN/lnGaN/GaN single quantum wells (QWs) and an InGaN/GaN single heterojunction were studied using continuous wave (CW) and pulsed photoluminescence in both edge and surface emitting configurations. Samples were grown on c-plane sapphire substrates by atmospheric pressure metalorganic chemical vapor deposition (MOCVD). Room temperature and 77K PL measurements were performed using a CW Ar-ion laser (305 nm) and a frequency tripled (280 nm), pulsed, mode-locked Ti: sapphire laser. CW PL emission spectra from the quantum wells (24, 30, 80Å) were all blue shifted with respect to the reference sample. The difference (i. e., the blue shift) between the measured value of peak emission energy from the QW and the band-edge emission from the reference sample was attributed to quantum size effects, and to strain arising due to a significant lattice mismatch between InGaN and GaN. In addition, stimulated emission was observed from an InGaN/GaN single heterojunction in the edge and surface emitting configu-ration at 77K. The narrowing of emission spectra, the nonlinear dependence of output emission intensity on input power density, and the observation of a strongly polarized output are presented. 相似文献
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《Photonics Technology Letters, IEEE》2009,21(20):1526-1528
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Farahmand M. Brennan K.F. Gebara E. Deukhyoun Heo Young Suh Laskar J. 《Electron Devices, IEEE Transactions on》2001,48(9):1844-1849
RF-breakdown was studied in bulk GaN and in GaN MESFETs using a full band Monte Carlo simulator. It was found that in bulk materials, increasing the frequency of an applied RF field would result in a lower overall impact ionization rate and consequently lead to higher breakdown fields. It was also found that the RF-breakdown voltage of devices increases with increasing frequency of the applied large signal RF excitation. The frequency dependence of RF-breakdown and the difference between RF and dc-breakdown is explained based on the time response of the particle energy to the change in the applied RF excitation 相似文献
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GaN HEMT reliability 总被引:2,自引:0,他引:2
This paper reviews the experimental evidence behind a new failure mechanism recently identified in GaN high-electron mobility transistors subject to electrical stress. Under high voltage, it has been found that electrically active defects are generated in the AlGaN barrier or at its surface in the vicinity of the gate edge. These defects reduce the drain current, increase the parasitic resistance and provide a path for excess gate current. There is mounting evidence for the role of the inverse piezoelectric effect in introducing mechanical stress in the AlGaN barrier layer and eventually producing these defects. The key signature of this mechanism is a sudden and non-reversible increase in the gate leakage current of several orders of magnitude. This degradation mechanism is voltage driven and characterized by a critical voltage below which degradation does not occur. This hypothesis suggests several paths to enhance the electrical reliability of GaN HEMTs which are borne out by experiments. 相似文献