应用于AlGaN/GaN HEMTs MMIC薄膜电阻的特性与可靠性

TaN和NiCr是AlGaN/GaN HEMTs微波集成电路中薄膜电阻最为常用的两种材料.文中对比了在SiC衬底上生长的这两种材料的薄膜电阻的可靠性.通过TaN和NiCr薄膜电阻的对比,发现TaN薄膜电阻的方块电阻(Rs)随着退火温度的上升而增大,然而NiCr薄膜电阻的Rs却出现相反的趋势.同时发现随着退火温度的上升TaN薄膜电阻的s.和接触电阻(Rc)的变化远远小于NiCr薄膜电阻的变化.在400℃退火及等离子刻蚀机的氧等离子暴露后,TaN薄膜电阻的Rs只下降了0.7Ω,大概2.56%,并且Rc上升了0.1Ω,大概6.6%.但是NiCr薄膜电阻的Rs.和Rc在不同的退火条件下经过氧等离子暴露后发生了很大的变化.因此,TaN薄膜电阻在氮气保护下经过400℃退火后在氧等离子暴露下更为稳定.     

TaN微波薄膜技术改善电阻元件

TaNFilm薄膜技术采用自钝化氮化钽,能制造在高温下具有长期稳定性和准确性的电阻元件。美国TT电子公司IRC先进薄膜分公司开发的这项技术可以制造在电信、航天和联网等微波应用中性能远远高于其他钝化膜技术的薄膜电路和混合衬底。     

X-波段AlGaN/GaN HEMT 功率MMIC

AlGaN/GaN高电子迁移率晶体管(HEMT)以其高输出功率密度、高电压工作和易于宽带匹配优势将成为下一代高频固态微波功率器件.     

X-波段AlGaN/GaN HEMT功率MMIC

AlGaN/GaN高电子迁移率晶体管(HEMT)以其高输出功率密度、高电压工作和易于宽带匹配等优势将成为下一代高频固态微波功率器件.微波功率器件主要有内匹配功率管和功率单片微波集成电路(MMIC)两种结构形式,功率MMIC尽管其研制成本相对较高,但功率MMIC可实现宽带匹配,同时功率MMIC的体积较内匹配功率管小得多,是满足诸如X波段TlR组件应用不可或缺的结构形式.功率MMIC的结构形式主要有微带和共面波导(CPW)两种,相比于CPW结构,微带结构的MMIC芯片面积更小,特别是对于大栅宽器件,微带结构的通孔接地更有利于寄生参量的减小,有利于提高MMIC的性能,因此微带结构也是应用更为广泛的MMIC结构形式.     

X-波段AlGaN/GaN HEMT功率MMIC

<正>AlGaN/GaN高电子迁移率晶体管(HEMT)以其高输出功率密度、高电压工作和易于宽带匹配等优势将成为下一代高频固态微波功率器件。微波功率器件主要有内匹配功率管和功率单片微波集成电路(MMIC)两种结构形式,功率MMIC尽管其研制成本相对较高,但功率MMIC可实现宽带匹配,同时功率MMIC的体积较内匹配功率管小得多,是满足诸如X     

TaN薄膜电阻的功率加载特性研究

通过射频反应溅射,在氧化铝基板上制备了TaN薄膜电阻。研究了TaN薄膜电阻在不同加载功率密度下表面温度的变化,研究了高温下TaN薄膜氧化所造成的电阻失效。按照混合集成电路规范的测试条件,在环境温度为70℃,TaN薄膜电阻的厚度为0.1μm,氧化铝基板厚度为0.125mm的条件下,TaN薄膜电阻可以耐受4W/mm2的功率密度,或者9.4W/mm2的1min瞬时功率密度冲击。     

高性能1mm AlGaN/GaN功率HEMTs研制

报道了基于蓝宝石衬底的高性能1mm AlGaN/GaN HEMTs功率器件.为了提高微波功率器件性能，采用新的欧姆接触和新型空气桥方案．测试表明，器件电流密度为0.784A/mm，跨导197mS/mm，击穿电压大于40V，截止态漏电较小，1mm栅宽器件的单位截止频率达到20GHz，最大振荡频率为28GHz，功率增益为11dB，功率密度为1.2W/mm,PAE为32%,两端口阻抗特性显示了在微波应用中的良好潜力．     

薄膜电阻网络稳定性和可靠性研究

本文通过对薄膜电阻网络稳定性和可靠性的研究，分析了影响薄膜电阻网络稳定性和可靠性的因素。通过在蒸发过程中合理地控制几个关键工艺参数、选择合适的热处理条件等方法，能够实现电阻网络长期稳定性和可靠性的提高。     

14W X波段AlGaN/GaN HEMT功率MMIC

报道了研制的SiC衬底AIGaN/GaN HEMT微带结构微波功率MMIC,芯片工艺采用凹槽栅场板结构提高AlGaN/GaNHEMTs的微波功率特性.S参数测试结果表明AlGaN/GaN HEMTs的频率特性随器件的工作电压变化显著.研制的该2级功率MMIC在9～11GHz带内30V工作,输出功率大于10W,功率增益大于12dB,带内峰值输出功率达到14.7W,功率增益为13.7dB,功率附加效率为23%,该芯片尺寸仅为2.0mm×1.1mm.与已发表的X波段AlGaN/GaN HEMT功率MMIC研制结果相比,本项工作在单位毫米栅宽输出功率和芯片单位面积输出功率方面具有优势.     

MMIC用多层磁膜电感研究

采用磁控溅射生长磁膜工艺,结合BCB(苯并环丁烯)平坦化技术,首次制作了"金属线圈/磁膜/金属线圈(M/F/M)"和"磁膜/金属线圈/磁膜/金属线圈(F/M/F/M)"两种结构的多层磁膜电感,整个工艺与标准MMIC工艺兼容.在2 GHz处,"金属线圈/磁膜/金属线圈"结构电感的电感量为7.5 nH,品质因数为7.17,...     

GaAs MMIC可靠性研究与进展

介绍了GaAs器件及MMIC的可靠性研究现状 ,给出了GaAs器件的几种失效模式和失效机理     

Current Collapse and High-Electric-Field Reliability of Unpassivated GaN/AlGaN/GaN HEMTs

Long-term ON-state and OFF-state high-electric-field stress results are presented for unpassivated GaN/AlGaN/GaN high-electron-mobility transistors on SiC substrates. Because of the thin GaN cap layer, devices show minimal current-collapse effects prior to high-electric-field stress, despite the fact that they are not passivated. This comes at the price of a relatively high gate-leakage current. Under the assumption that donor-like electron traps are present within the GaN cap, two-dimensional numerical device simulations provide an explanation for the influence of the GaN cap layer on current collapse and for the correlation between the latter and the gate-leakage current. Both ON-state and OFF-state stresses produce simultaneous current-collapse increase and gate-leakage-current decrease, which can be interpreted to be the result of gate-drain surface degradation and reduced gate electron injection. This study shows that although the thin GaN cap layer is effective in suppressing surface-related dispersion effects in virgin devices, it does not, per se, protect the device from high-electric-field degradation, and it should, to this aim, be adopted in conjunction with other technological solutions like surface passivation, prepassivation surface treatments, and/or field-plate gate     

AlN薄膜对TaN薄膜电阻器功率影响研究

利用直流磁控溅射,在镍锌铁氧体基片上制作的TaN薄膜电阻器,受到铁氧体表面及内部结构特性差且导热系数低的影响,功率密度只能达到0.91 W/mm~2。利用射频磁控溅射,在铁氧体基片与薄膜电阻器间镀上1.5μm厚的AlN薄膜缓冲层,可有效改善基片的表面特性及散热能力。带AlN薄膜缓冲层的TaN薄膜电阻器的功率密度可达3.76 W/mm~2。     

AlGaN/GaN HEMTs With Thin InGaN Cap Layer for Normally Off Operation

AlGaN/GaN HEMTs with a thin InGaN cap layer have been proposed to implement the normally off HEMTs. The key idea is to employ the polarization-induced field in the InGaN cap layer, by which the conduction band is raised, which leads to the normally off operation. The fabricated HEMT with an In_0.2Ga_0.8N cap layer with a thickness of 5 nm showed normally off operation with a threshold voltage of 0.4 V and a maximum transconductance of 85 mS/mm for the device with a 1.9-mum-long gate. By etching off the In_0.2Ga_0.8N cap layer at the access region using gate electrode as an etching mask, the maximum transconductance has increased from 85 to 130 mS/mm due to a reduction of the parasitic source resistance.     

基于AlGaN/GaN HEMT的源漏整体刻蚀欧姆接触结构

研究了源漏整体刻蚀欧姆接触结构对AlGaN/GaN高电子迁移率晶体管(HEMT)的欧姆接触电阻和金属电极表面形貌的影响.利用传输线模型(TLM)对样品的电学性能进行测试,使用原子力显微镜(AFM)对样品的表面形貌进行表征,通过透射电子显微镜(TEM)和X射线能谱仪(EDS)对样品的剖面微结构和界面反应进行表征与分析.实验结果显示,采用Ti/Al/Ni/Au(20 nm/120 nm/45 nm/55 nm)金属和源漏整体刻蚀欧姆接触结构,在合金温度870 c℃,升温20 s,退火50 s条件下,欧姆接触电阻最低为0.13 Ω·mm,方块电阻为363.14 Ω/□,比接触电阻率为4.54×10-7Ω·cm2,形成了良好的欧姆接触,降低了器件的导通电阻.     

Reliability of 100 nm AlGaN/GaN HEMTs for mm-wave applications

The effect of gate metallization and gate shape on the reliability and RF performance of 100 nm AlGaN/GaN HEMTs on SiC substrate for mm-wave applications has been investigated under on-state DC-stress tests. By replacing the gate metallization from NiPtAu to PtAu the median time to failure at T_ch = 209 °C can be improved from 10 h to more than 1000 h. Replacing the PtAu T-gate by a spacer gate further reduces the degradation rate under on-state stress, but decreases the current-gain cut-off frequency from 75 GHz to 50 GHz. Physical failure analysis using electroluminescence and TEM cross-section revealed pit and Ni void formation at the gate foot as the main degradation mechanisms of devices with NiPtAu T-gate. High resolution EDX mapping of stressed devices indicates that the formation of pits is caused by a local aluminium oxidation process. Simulation of the stress induced changes of the input characteristics of devices with NiPtAu gate further proves the formation of pits and Ni voids.     

Full-Wafer Characterization of AlGaN/GaN HEMTs on Free-Standing CVD Diamond Substrates

We report on electrical characterization and uniformity measurements of the first conventionally processed AlGaN/GaN high electron mobility transistors (HEMTs) on free-standing chemical-vapor-deposited (CVD) diamond substrate wafers. DC and RF device performance is reported on HEMTs fabricated on $sim!!hbox{130-}muhbox{m}$-thick and 30-mm round CVD diamond substrates without mechanical carrying wafers. A measured $f_{T} cdot L_{G}$ product of 12.5 $hbox{GHz} cdot muhbox{m}$ is the best reported data for all GaN-on-diamond technology. X-band power performance of AlGaN/GaN HEMTs on diamond is reported to be 2.08 W/mm and 44.1% power added efficiency. This letter demonstrates the potential for GaN HEMTs to be fabricated on CVD diamond substrates utilizing contact lithography process techniques. Further optimization of the epitaxy and diamond substrate attachment process could provide for improvements in thermal spreading while preserving the electrical properties.