磁控溅射AlN介质MIS栅结构的AlGaN/GaN HEMT

报道了一种X波段输出功率密度达10.4W/mm的SiC衬底AlGaN/GaN MIS-HEMT。器件研制中采用了MIS结构、凹槽栅以及场板,其中MIS结构中采用了磁控溅射的AlN介质作为绝缘层。采用MIS结构后,器件击穿电压由80V提高到了180V以上,保证了器件能够实现更高的工作电压。在8GHz、55V的工作电压下,研制的1mm栅宽AlGaN/GaN MIS-HEMT输出功率达到了10.4W,此时器件的功率增益和功率附加效率分别达到了6.56dB和39.2%。     

凹槽栅场调制板结构AlGaN/GaN HEMT

研制的SiC衬底上的AlGaN/GaN微波功率HEMTs,采用凹槽栅和场调制板结构有效抑制了器件的电流崩塌,提高了器件的击穿电压和器件的微波功率特性.研制的1mm栅宽器件在8GHz,34V工作电压下,饱和输出功率达到了9.05W,功率增益为7.5dB,功率附加效率为46%.     

凹槽栅场调制板结构AlGaN/GaN HEMT

研制的SiC衬底上的AlGaN/GaN微波功率HEMTs,采用凹槽栅和场调制板结构有效抑制了器件的电流崩塌,提高了器件的击穿电压和器件的微波功率特性.研制的1mm栅宽器件在8GHz,34V工作电压下,饱和输出功率达到了9.05W,功率增益为7.5dB,功率附加效率为46%.     

磁控溅射AIN介质MIS栅结构的AlGaN/GaN HEMT

报道了一种X波段输出功率密度达10.4 W/mm的SiC衬底AIGaN/GaN MIS-HEMT,器件研制中采用了MIS结构、凹槽栅以及场板,其中MIS结构中采用了磁控溅射的A1N介质作为绝缘层.采用MIS结构后,器件击穿电压由80 V提高到了180 V以上,保证了器件能够实现更高的工作电压.在8 GHz、55 V的工作电压下,研制的1 mm栅宽AlGaN/GaN MIS-HEMT输出功率达到了10.4 W,此时器件的功率增益和功率附加效率分别达到了6.56 dB和39.2%.     

X波段高输出功率凹栅AlGaN/GaN HEMT

使用自主研制的SiC衬底GaN HEMT外延材料,研制出高输出功率AlGaN/GaN HEMT,优化了器件研制工艺,比接触电阻率小于1.0×10-6Ω·cm2,电流崩塌参量小于10%,击穿电压大于80V.小栅宽器件工作电压达到40V,频率为8GHz时输出功率密度大于10W/mm.栅宽为2mm单胞器件,工作电压为28V,频率为8GHz时,输出功率为12.3W,功率增益为4.9dB,功率附加效率为35%.四胞内匹配总栅宽为8mm器件,工作电压为27V时,频率为8GHz时,输出功率为33.8W,功率增益为6.3dB,功率附加效率为41.77%,单胞器件和内匹配器件输出功率为目前国内该器件输出功率的最高结果.     

磁控溅射AIN介质的14W／mm AlGaN／GaN MIS-HEMT

介绍了一种采用磁控溅射AlN介质作为绝缘层的的SiC衬底AlGaN／GaN MIS-HEMT。器件研制中采用了凹槽栅和场板结构。采用MIS结构后,器件击穿电压由80V提高到了180V以上,保证了器件能够实现更高的工作电压。在2GHz、75V工作电压下,研制的200μm栅宽AlGaN／GaNMIS-HEMT输出功率密度达到了14．4W／mm,器件功率增益和功率附加效率分别为20．51dB和54．2％。     

X波段高输出功率凹栅AlGaN/GaN HEMT

使用自主研制的SiC衬底GaN HEMT外延材料,研制出高输出功率AlGaN/GaN HEMT,优化了器件研制工艺,比接触电阻率小于1.0×10-6Ω·cm2,电流崩塌参量小于10%,击穿电压大于80V.小栅宽器件工作电压达到40V,频率为8GHz时输出功率密度大于10W/mm.栅宽为2mm单胞器件,工作电压为28V,频率为8GHz时,输出功率为12.3W,功率增益为4.9dB,功率附加效率为35%.四胞内匹配总栅宽为8mm器件,工作电压为27V时,频率为8GHz时,输出功率为33.8W,功率增益为6.3dB,功率附加效率为41.77%,单胞器件和内匹配器件输出功率为目前国内该器件输出功率的最高结果.     

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.     

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.     

非掺杂AlGaN/GaN微波功率HEMT

报道了研制的AlGaN/GaN微波功率HEMT,该器件采用以蓝宝石为衬底的非掺杂AlGaN/GaN异质结构,器件工艺采用了Ti/Al/Ni/Au欧姆接触和Ni/Au肖特基势垒接触以及SiN介质进行器件的钝化.研制的200μm栅宽T型布局AlGaN/GaN HEMT在1.8GHz,Vds=30V时输出功率为28.93dBm,输出功率密度达到3.9W/mm,功率增益为15.59dB,功率附加效率(PAE)为48.3%.在6.2GHz,Vds=25V时该器件输出功率为27.06dBm,输出功率密度为2.5W/mm,功率增益为10.24dB,PAE为35.2%.     

具有场板结构的AlGaN/GaN HEMT的直流特性

研制成功具有场板结构的AIGaN/GaN HEMT器件,对源场板、栅场板器件的性能进行了分析.场板的引入减小了器件漏电和肖特基漏电,提高了肖特基反向击穿电压.源漏间距4靘的HEMT的击穿电压由常规器件的65V提高到100V以上,肖特基反向漏电由37霢减小到5.7霢,减小了一个量级.肖特基击穿电压由常规结构的78V提高到100V以上.另外,还初步讨论了高频特性.     

用于功率变换的高击穿增强型AlGaN/GaN HEMTs

首次采用CF4等离子体技术实现可用于功率变换的增强性AlGaN/GaN功率器件。实验结果表明,当AlGaN/GaN器件经功率150W和时间150s等离子体轰击后,器件阈值电压从-4V被调制约为0.5V,表现为增强型。当漂移区LGD从5μm增加到15μm,器件的击穿电压从50V迅速增大到400V,电压增幅达350V。采用长度为3μm源场板结构将器件击穿电压明显地提高,击穿电压增加约为475V,且有着比硅基器件更低的比导通电阻,约为2.9mΩ.cm2。器件模拟结果表明,因源场板在远离栅边缘的漂移区中引入另一个电场强度为1.5MV/cm的电场,从而有效地释放了存在栅边缘的电场,将高达3MV/cm的电场减小至1MV/cm。微波测试结果表明,器件的特征频率fT和最大震荡频率fMAX随Vgs改变,正常工作时两参数均在千兆量级。栅宽为1mm的增强型功率管有较好的交直流和瞬态特性,正向电流约为90mA。故增强型AlGaN/GaN器件适合高压高频大功率变换的应用。     

High Breakdown Voltage Achieved on AlGaN/GaN HEMTs With Integrated Slant Field Plates

A self-aligned “slant-field-plate” technology is presented as an improvement over the discrete multiple field plates for high breakdown voltage AlGaN/GaN HEMTs. Devices were tested in Fluorinert to eliminate the breakdown of air, which was identified to limit the breakdown voltage in AlGaN/GaN HEMTs. A single integrated field plate, which is self-aligned with the gate, is shown to support more than a kilovolt breakdown voltage ($V_ br$up to 1900 V was measured with Fluorinert). Devices made with this technology show a good large signal-frequency behavior. Various issues regarding breakdown measurements and interpretation of measurement results are presented.     

0.15μm GaN HEMT及其应用

报道了毫米波应用的0.15μm场板结构GaN HEMT。器件研制采用了76.2mm(3英寸)SiC衬底上外延生长的AlGaN/GaN异质结构材料,该材料由MOCVD技术生长并引入了掺Fe GaN缓冲层技术以提升器件击穿电压。器件栅脚和集成了场板的栅帽均由电子束光刻实现,并采用栅挖槽技术来控制器件夹断电压。研制的2×75μm栅宽GaN HEMT在24V工作电压、35GHz频率下的负载牵引测试结果显示其输出功率密度达到了4W/mm,对应的功率增益和功率附加效率分别为5dB和35%。采用该0.15μm GaN HEMT技术进行了Ka波段GaN功率MMIC的研制,所研制的功率MMIC在24V工作电压下脉冲工作时(100μs脉宽、10%占空比),29GHz频点处饱和功率达到了10.64W。     

Monolithically integrated enhancement/depletion-mode AIGaN/GaN HEMT D flip-flop using fluorine plasma treatment

Depletion-mode and enhancement-mode AlGaN/GaN HEMTs using fluorine plasma treatment were integrated on one wafer. Direct-coupled FET logic circuits, such as an E/D HEMT inverter, NAND gate and D flip-flop, were fabricated on an AlGaN/GaN heterostructure. The D flip-flop and NAND gate are demonstrated in a GaN system for the first time. The dual-gate AlGaN/GaN E-HEMT substitutes two single-gate E-HEMTs for simplifying the NAND gate and shrinking the area, integrating with a conventional AlGaN/GaN D-HEMT and demonstrating a NAND gate. E/D-mode D flip-flop was fabricated by integrating the inverters and the NAND gate on the AlGaN/GaN heterostructure. At a supply voltage of 2 V, the E/D inverter shows an output logic swing of 1.7 V, a logic-low noise margin of 0.49 V and a logic-high noise margin of 0.83 V. The NAND gate and D flip-flop showed correct logic function demonstrating promising potential for GaN-based digital ICs.     

F等离子体处理增强型及耗尽型AlGaN/GaN HEMT集成的D触发器

耗尽型和F等离子体处理增强型高电子迁移率晶体管（HEMT）被集成在同一圆片上。增强型/耗尽型 HEMT反向器、与非门以及D触发器等直接耦合场效应晶体管逻辑电路被制作在AlGaN/GaN异质结上。D触发器在GaN体系中首次被实现。在电源电压为2伏的条件下,增强型/耗尽型反向器显示输出逻辑摆幅为1.7伏,逻辑低噪声容限为0.49伏,逻辑高噪声容限为0.83伏。与非门和D触发器的功能正确,证实了GaN基数字电路的发展潜力。     

PI/Cr钝化对提高AlGaN/GaN HEMTs 击穿电压的研究

A novel AlGaN/GaN high electric mobility transistor（HEMT） with polyimide（PI）/chromium（Cr） as thepassivationlayerisproposedforenhancingbreakdownvoltageanditsDCperformanceisalsoinvestigated.The Cr nanoparticles firstly introduced in PI thin films by the co-evaporation can be used to increase the permittivity of PI film. The high-permittivity PI/Cr passivation acting as field plate can suppress the fringing electric field peak at the drain-side edge of the gate electrode. This mechanism is demonstrated in accord with measured results. The experimental results show that in comparison with the AlGaN/GaN HEMTs without passivation, the breakdown voltage of HEMTs with the PI/Cr composite thin films can be significantly improved, from 122 to 248 V.     

Recessed-gate structure approach toward normally off high-Voltage AlGaN/GaN HEMT for power electronics applications

A recessed-gate structure has been studied with a view to realizing normally off operation of high-voltage AlGaN/GaN high-electron mobility transistors (HEMTs) for power electronics applications. The recessed-gate structure is very attractive for realizing normally off high-voltage AlGaN/GaN HEMTs because the gate threshold voltage can be controlled by the etching depth of the recess without significant increase in on-resistance characteristics. With this structure the threshold voltage can be increased with the reduction of two-dimensional electron gas (2DEG) density only under the gate electrode without reduction of 2DEG density in the other channel regions such as the channel between drain and gate. The threshold-voltage increase was experimentally demonstrated. The threshold voltage of fabricated recessed-gate device increased to -0.14 V while the threshold voltage without the recessed-gate structure was about -4 V. The specific on-resistance of the device was maintained as low as 4 m/spl Omega//spl middot/cm/sup 2/ and the breakdown voltage was 435 V. The on-resistance and the breakdown voltage tradeoff characteristics were the same as those of normally on devices. From the viewpoint of device design, the on-resistance for the normally off device was modeled using the relationship between the AlGaN layer thickness under the gate electrode and the 2DEG density. It is found that the MIS gate structure and the recess etching without the offset region between recess edge and gate electrode will further improve the on-resistance. The simulation results show the possibility of the on-resistance below 1 m/spl Omega//spl middot/cm/sup 2/ for normally off AlGaN/GaN HEMTs operating at several hundred volts with threshold voltage up to +1 V.     

栅槽刻蚀工艺对增强型GaN HEMT器件性能的影响

基于凹槽栅增强型氮化镓高电子迁移率晶体管(GaN HEMT)研究了不同的栅槽刻蚀工艺对GaN器件性能的影响。在栅槽刻蚀方面,采用了一种感应耦合等离子体(ICP)干法刻蚀技术与高温热氧化湿法刻蚀技术相结合的两步法刻蚀技术,将AlGaN势垒层全部刻蚀掉,制备出了阈值电压超过3 V的增强型Al_2O_3/AlGaN/GaN MIS-HEMT器件。相比于传统的ICP干法刻蚀技术,两步法是一种低损伤的自停止刻蚀技术,易于控制且具有高度可重复性,能够获得更高质量的刻蚀界面,所制备的器件增强型GaN MIS-HEMT器件具有阈值电压回滞小、电流开关比(I_ON/I_OFF)高、栅极泄漏电流小、击穿电压高等特性。