The origin of the piezoelectric effect of GaAs is discussed in some detail.TheGa atoms are negatively charged and As atoms positively charged.The piezoelectric con-stant tensors for arbitrarily oriented GaAs have been...The origin of the piezoelectric effect of GaAs is discussed in some detail.TheGa atoms are negatively charged and As atoms positively charged.The piezoelectric con-stant tensors for arbitrarily oriented GaAs have been obtained.It is verified that for nor-mal stress when the GaAs samples are oriented in the 〈111〉 direction the maximumpiezoelectric effect occurs.As far as the piezoelectric properties and fabrication technologyare concerned,〈100〉 oriented GaAs substratcs are fit for the force sensors.展开更多
基于表面沟道型平面肖特基势垒二极管基本结构,采用GaAs 0.15μm伪高电子迁移率晶体管(pseudomorphic high electron mobility transistors,pHEMT)工艺制程,提出了一种垂直沟道长跨度空气桥的肖特基二极管模型.研究了不同阳极直径对肖...基于表面沟道型平面肖特基势垒二极管基本结构,采用GaAs 0.15μm伪高电子迁移率晶体管(pseudomorphic high electron mobility transistors,pHEMT)工艺制程,提出了一种垂直沟道长跨度空气桥的肖特基二极管模型.研究了不同阳极直径对肖特基二极管级联电阻的影响,对比分析了不同焊盘间距下肖特基二极管模型的S参数仿真结果,得到最优空气桥长度;仿真了最优焊盘间距下二极管肖特基结的TCAD模型,根据仿真得到的特性曲线提取肖特基二极管的SPICE参数.经实验测试,该二极管具有极低的零偏置结电容,截止频率高达9 THz,仿真结果与实测结果吻合度较高,可用于太赫兹频段上.展开更多
设计并实现了一款宽带低噪声放大器,采用单级负反馈拓扑结构以提高增益平坦度和稳定性。为进一步简化应用,电路采用电阻自偏压技术实现单电源供电。此外,为优化增益及噪声系数,从低噪声放大器设计理论出发,利用遗传算法对无源元件取值...设计并实现了一款宽带低噪声放大器,采用单级负反馈拓扑结构以提高增益平坦度和稳定性。为进一步简化应用,电路采用电阻自偏压技术实现单电源供电。此外,为优化增益及噪声系数,从低噪声放大器设计理论出发,利用遗传算法对无源元件取值进行了优化。该放大器采用0.25μm PHEMT GaAs工艺实现,芯片面积为1 mm×1.2 mm。测试结果表明,采用5 V单电源电压供电,总工作电流为30 m A,在30-3 000 MHz频率范围内,该放大器增益大于13 d B,噪声系数小于2.1 d B,输入反射系数小于-8.5 d B,输出反射系数小于-10 d B,1 d B压缩点输出功率大于7 d Bm。展开更多
文摘The origin of the piezoelectric effect of GaAs is discussed in some detail.TheGa atoms are negatively charged and As atoms positively charged.The piezoelectric con-stant tensors for arbitrarily oriented GaAs have been obtained.It is verified that for nor-mal stress when the GaAs samples are oriented in the 〈111〉 direction the maximumpiezoelectric effect occurs.As far as the piezoelectric properties and fabrication technologyare concerned,〈100〉 oriented GaAs substratcs are fit for the force sensors.
文摘基于表面沟道型平面肖特基势垒二极管基本结构,采用GaAs 0.15μm伪高电子迁移率晶体管(pseudomorphic high electron mobility transistors,pHEMT)工艺制程,提出了一种垂直沟道长跨度空气桥的肖特基二极管模型.研究了不同阳极直径对肖特基二极管级联电阻的影响,对比分析了不同焊盘间距下肖特基二极管模型的S参数仿真结果,得到最优空气桥长度;仿真了最优焊盘间距下二极管肖特基结的TCAD模型,根据仿真得到的特性曲线提取肖特基二极管的SPICE参数.经实验测试,该二极管具有极低的零偏置结电容,截止频率高达9 THz,仿真结果与实测结果吻合度较高,可用于太赫兹频段上.
文摘设计并实现了一款宽带低噪声放大器,采用单级负反馈拓扑结构以提高增益平坦度和稳定性。为进一步简化应用,电路采用电阻自偏压技术实现单电源供电。此外,为优化增益及噪声系数,从低噪声放大器设计理论出发,利用遗传算法对无源元件取值进行了优化。该放大器采用0.25μm PHEMT GaAs工艺实现,芯片面积为1 mm×1.2 mm。测试结果表明,采用5 V单电源电压供电,总工作电流为30 m A,在30-3 000 MHz频率范围内,该放大器增益大于13 d B,噪声系数小于2.1 d B,输入反射系数小于-8.5 d B,输出反射系数小于-10 d B,1 d B压缩点输出功率大于7 d Bm。
