AlGaN/GaN HEMT场板结构对与表面态相关的延迟特性的影响

为了研究AlGaN/GaN HEMT器件中场板结构对电流崩塌效应影响的物理机理,我们运用数值模拟的方法研究了场板结构和与表面态相关的栅延迟现象之间的关系。模拟显示场板结构可以显著地抑制电流崩塌效应的强度,但是对延迟时间没有影响。场板结构可以增大AlGaN表面附近的空穴积累,导致表面态的离化率增大从而抑制器件的电流崩塌。     

Optimized power simulation of AlGaN/GaN HEMT for continuous wave and pulse applications

An optimized modeling method of 8 × 100 μm AlGaN/GaN-based high electron mobility transistor (HEMT) for accurate continuous wave (CW) and pulsed power simulations is proposed. Since the self-heating effect can occur during the continuous operation, the power gain from the continuous operation significantly decreases when compared to a pulsed power operation. This paper extracts power performances of different device models from different quiescent biases of pulsed current-voltage (I-V) measurements and compared them in order to determine the most suitable device model for CW and pulse RF microwave power amplifier design. The simulated output power and gain results of the models at V_gs = -3.5 V, V_ds = 30 V with a frequency of 9.6 GHz are presented.     

AlGaN/GaN HEMT结构热时间常数谱提取方法的研究

利用电学法对AlGaN/GaN 高电子迁移率晶体管(HEMTs)有源区瞬态温升进行测量.利用非参数拟合算法—局部加权回归散点平滑法(LOWESS)对原始测量数据进行平滑去噪处理,进而得到热时间常数谱,分析AlGaN/GaN HEMTs热传导路径物理结构。与传统平滑去噪方法—多阶指数拟合相比,通过LOWESS算法得到的热时间常数谱更丰富,得到RC网络更多,进而热传导路径结构分析更精细。结果表明,LOWESS非参数拟合算法能够更好的去除测量数据噪声,保留原始离散数据细微的变化趋势。通过该方法所提取的热时间常数谱能描述AlGaN/GaN HEMTs有源区温度细微变化,帮助研究人员精确分析热传导路径层次构成。     

微波、毫米波GaN HEMT与MMIC的新进展

综述了近几年微波、毫米波氮化镓高电子迁移率晶体管(GaN HEMT)与单片微波集成电路(MMIC)在高效率、宽频带、高功率和先进热管理等方面的应用创新进展.介绍了基于GaN HEMT器件所具有的高功率密度和高击穿电压,采用波形工程原理设计的各类开关模式的高效率功率放大器,以及基于GaN HEMT器件的高功率密度、高阻抗的特点与先进的宽带拓扑电路和功率合成技术相结合的宽频带和高功率放大器.详细介绍了微波高端和毫米波段的高效率、宽频带和高功率放大器,多功能电路和多功能集成的GaN MMIC.最后阐述了由于GaN HEMT的功率密度是其他半导体器件的数倍,其先进热管理的创新研究也成为热点.     

Ku波段宽带氮化镓功率放大器MMIC

基于0.25μm栅长GaN HEMT工艺,采用三级放大拓扑结构设计了一款Ku波段GaN功率放大器.放大器设计从建立大信号模型出发,输出匹配网络和级间匹配网络均采用电抗匹配减小电路的损耗,从而提高整体放大器的功率效率.测试结果表明,该放大器在14.6~18GHz频带内,小信号增益30dB,脉冲饱和输出功率达15W,功率附加效率(PAE)大于32%;在14.8GHz频点处,放大器的峰值功率达19.5W,PAE达39%.该结果表明GaN MMIC具有高频高功率高效率的优势,具有广阔的应用前景.     

Wearable Multiparameter Platform Based on AlGaN/GaN High‐electron‐mobility Transistors for Real‐time Monitoring of pH and Potassium Ions in Sweat

Biosensors based on field‐effect transistor (FET) structures have attracted considerable attention because they offer rapid, inexpensive parallel sensing and ultrasensitive label‐free detection. However, long‐term repeatable detection cannot be performed, and Ag/AgCl reference electrode design is complicated, which has hindered FET biosensors from becoming truly wearable health‐monitoring platforms. In this paper, we propose a novel wearable detection platform based on AlGaN/GaN high‐electron‐mobility transistors (HEMTs). In this platform, a sweatband was used to continuously collect sweat, and a pH detecting unit and a potassium ion detecting unit were formed by modifying different sensitive films to realize the long‐term stable and repeatable detection of pH and potassium ions. Experimental data show that the wearable detection platform based on AlGaN/GaN HEMTs has good sensitivity (pH 3–7 sensitivity is 45.72 μA/pH; pH 7.4–9 sensitivity is 51.073 μA/pH; and K⁺ sensitivity is 4.94 μA/lgα_K⁺), stability (28 days) and repeatability (the relative standard deviation (RSD) of pH 3–7 sensitivity is 2.6 %, the RSD of pH 7.4–9 sensitivity is 2.1 %, and the RSD of K⁺ sensitivity is 7.3 %). Our newly proposed wearable platform has excellent potential for predictive analytics and personalized medical treatment.     

GaN HEMT器件封装技术研究进展

GaN高电子迁移率晶体管(HEMT)器件由于其宽禁带材料的独特性能,相比硅功率器件具有击穿场强高、导通电阻低、转换速度快等优势,在智能家电、交直流转换器、光伏逆变器以及电动汽车等领域有着广泛的应用前景.但GaN HEMT器件的高功率密度和高频工作特性,给器件封装带来了极大挑战,要使其出色性能得以充分发挥,其封装结构、材...     

金刚石衬底上GaN HEMT沟道温度建模:各向异性且非均匀热导率的影响

为了改善GaN HEMT的自热效应,集成高热导率的金刚石衬底有助于增强器件有源区的热量耗散。然而,化学气相淀积(CVD)生长的多晶金刚石(PCD)具有柱状晶粒结构,导致了各向异性的材料热导率,且其热导率值与生长厚度有关。为此,通过建模金刚石生长过程中晶粒尺寸的演变过程,计算了金刚石沿面内和截面方向的热导率。基于该PCD热导率模型,利用计入材料非线性热导率的GaN器件热阻解析模型,计算得到了GaN HEMT沟道温度的波动范围,并分析了其与器件结构(栅长、栅宽、栅间距、衬底厚度)和功耗的依赖关系。最后,通过与有限元(FEM)仿真结果对比,分区域提取了GaN HEMT器件中PCD衬底的有效热导率,分别为260~310 W/(m·K)和1 250~1 450 W/(m·K)。本文的计算为预测金刚石衬底上GaN HEMT器件的沟道温度提供了快速、有效的方法。     

多谐波失真模型应用研究

基于非线性大信号散射函数理论,对一种用来线性化散射函数的新方法进行了研究.另外,在弱非线性条件下,与相位归一化和线性化技术相结合,分析了极坐标系下线性化表达式的各部分功能,并预测了输出散射波所应该具有的特性.最后,利用实际HEMT晶体管的测量数据说明了应用多谐波失真模型对精确分析非线性器件的重要意义.     

A Ka-band 22 dBm GaN amplifier MMIC

A Ka-band GaN amplifier MMIC has been designed in CPW technology,and fabricated with a domestic GaN epitaxial wafer and process.This is,to the best of our knowledge,the first demonstration of domestic Kaband GaN amplifier MMICs.The single stage CPW MMIC utilizes an AlGaN/GaN HEMT with a gate-length of 0.25μm and a gate-width of 2×75μm.Under V_ds=10 V,continuous-wave operating conditions,the amplifier has a 1.5 GHz operating bandwidth.It exhibits a linear gain of 6.3 dB,a maximum output power of 22 dBm and a peak PAE of 9.5%at 26.5 GHz.The output power density of the AlGaN/GaN HEMT in the MMIC reaches 1 W/mm at Ka-band under the condition of V_ds=10 V.