The ground-state energy level （GEL） and electron distribution of GaAs pseudomorphic high-electron-mobility transistors （PHEMTs） are analyzed by a self-consistent solution to the Schrodinger-Poisson equations. The ...The ground-state energy level （GEL） and electron distribution of GaAs pseudomorphic high-electron-mobility transistors （PHEMTs） are analyzed by a self-consistent solution to the Schrodinger-Poisson equations. The indium composition and thickness of the InGaAs channel are optimized according to the GEL position. The GEL position is not in direct proportion to 1/d^2 （d is the channel thickness） by considering the influence of electron distribution in the InGaAs channel. Indium composition 0.22 and channel thickness 9 nm are obtained by considering the mismatch between InGaAs and AlGaAs. Several PHEMT samples are grown according to the theoretical results and mobility 6300 cm^2 /V.s is achieved.展开更多
This work deals with the study of optical and morphological properties of InGaAs/AlGaAs quantum dot(QD) structures grown by molecular beam epitaxy(MBE) . Photoluminescence(PL) emission energies,activation energies of ...This work deals with the study of optical and morphological properties of InGaAs/AlGaAs quantum dot(QD) structures grown by molecular beam epitaxy(MBE) . Photoluminescence(PL) emission energies,activation energies of PL quenching and QD sizes are studied as functions of the Al content in the AlyGa1-yAs confining layers(CL) . We show that the PL emission energy of In(Ga) As/AlyGa1-yAs QD structures increases with increasing y and that the sizes of InAs/AlyGa1-yAs QDs decrease with increasing y. By the comparison of the experimental results with those of an effective-mass model developed to calculate the QD fundamental transition energies,we show that the blueshift of emission energy has to be ascribed not only to the increase in barrier discontinuities that confine the carriers into QDs but even to effects related to changes of the QD morphology dependent on CL composition. Moreover,we show that the Al content in the barriers determines also the activation energy of thermal quenching of PL,which depends on the thermal escape of carriers from QD levels. These studies resulted in the preparation of structures with efficient light-emission in the 980 nm spectral window of interest for lightwave communications.展开更多
The effect of drain-source voltage on A1GaAs/InGaAs PHEMTs thermal resistance is studied by experimental measuring and simulation. The result shows that A1GaAs/InGaAs PHEMTs thermal resistance presents a downward tren...The effect of drain-source voltage on A1GaAs/InGaAs PHEMTs thermal resistance is studied by experimental measuring and simulation. The result shows that A1GaAs/InGaAs PHEMTs thermal resistance presents a downward trend under the same power dissipation when the drain-source voltage （VDs） is decreased. Moreover, the relatively low VDS and large drain-source current （IDs） result in a lower thermal resistance. The chip-level and package-level thermal resistance have been extracted by the structure function method. The simulation result indicated that the high electric field occurs at the gate contact where the temperature rise occurs. A relatively low VDS leads to a relatively low electric field, which leads to the decline of the thermal resistance.展开更多
90-nm T-shaped gate InP-based In_（0.52）Al_（0.48）As/In_（0.6）Ga_（0.4）As pseudomorphic high electron mobility transistors were designed and fabricated with a gate-width of 2×30 μm,a source-drain space of 2...90-nm T-shaped gate InP-based In_（0.52）Al_（0.48）As/In_（0.6）Ga_（0.4）As pseudomorphic high electron mobility transistors were designed and fabricated with a gate-width of 2×30 μm,a source-drain space of 2.5 μm,and a source-gate space of 0.75 μm.DC,RF and small-signal model characterizations were demonstrated.The maximum saturation current density was measured to be 755 mA/mm biased at V_（gs）=0.6 V and V_（ds）=1.5 V.The maximum extrinsic transconductance was measured to be 1006 mS/mm biased at V_（ds）=—0.1V and V_（ds）=1.5 V.The extrapolated current gain cutoff frequency and maximum oscillation frequency based on S-parameters measured from 0.5 to 110 GHz were 180 and 264 GHz,respectively.The inflection point（the stability factor k=1）where the slope from-10 dB/decade（MSG） to-20 dB/decade（MAG） was measured to be 83 GHz.The smallsignal model of this device was also established,and the S-parameters of the model are consistent with those measured from 0.5-110 GHz.展开更多
A 50 MHz-1 GHz low noise and high linearity amplifier monolithic-microwave integrated-circuit （MMIC） for cable TV is presented.A shunt AC voltage negative feedback combined with source current negative feedback is a...A 50 MHz-1 GHz low noise and high linearity amplifier monolithic-microwave integrated-circuit （MMIC） for cable TV is presented.A shunt AC voltage negative feedback combined with source current negative feedback is adopted to extend the bandwidth and linearity.A novel DC bias feedback is introduced to stabilize the operation point,which improved the linearity further.The circuit was fabricated with a 0.15μm InGaAs PHEMT （pseudomorphic high electron mobility transistor） process.The test was carried out in 75Ωsystems from 50 MHz to 1 GHz.The measurement results showed that it gave a small signal gain of 16.5 dB with little gain ripples of less than±1dB.An excellent noise figure of 1.7-2.9 dB is obtained in the designed band.The IIP3 is 16 dBm, which shows very good linearity.The CSO and CTB are high up to 68 dBc and 77 dBc,respectively.The chip area is 0.56 mm^2 and the power dissipation is 110 mA with a 5 V supply.It is ideally suited to cable TV systems.展开更多
采用普通接触曝光研制成栅长为 0 .2 5 μm的 Ga As基 In Al As/ In Ga As变组分高电子迁移率晶体管(MHEMT) ,测得其跨导为 5 2 2 m S/ m m,沟道电流密度达 4 90 m A/ mm,截止频率为 75 GHz,比同样工艺条件下Ga As基 In Ga P/ In Ga As ...采用普通接触曝光研制成栅长为 0 .2 5 μm的 Ga As基 In Al As/ In Ga As变组分高电子迁移率晶体管(MHEMT) ,测得其跨导为 5 2 2 m S/ m m,沟道电流密度达 4 90 m A/ mm,截止频率为 75 GHz,比同样工艺条件下Ga As基 In Ga P/ In Ga As PHEMT的性能有很大的提高 .对该器件工艺及结果进行了分析 ,提取了器件的交流小信号等效电路模型参数 ,并提出了进一步得到高稳定性、高性能器件的方法 .展开更多
文摘The ground-state energy level （GEL） and electron distribution of GaAs pseudomorphic high-electron-mobility transistors （PHEMTs） are analyzed by a self-consistent solution to the Schrodinger-Poisson equations. The indium composition and thickness of the InGaAs channel are optimized according to the GEL position. The GEL position is not in direct proportion to 1/d^2 （d is the channel thickness） by considering the influence of electron distribution in the InGaAs channel. Indium composition 0.22 and channel thickness 9 nm are obtained by considering the mismatch between InGaAs and AlGaAs. Several PHEMT samples are grown according to the theoretical results and mobility 6300 cm^2 /V.s is achieved.
基金The work has been partially supported by the "SANDiE" Networkof Excellence of EU (contract No. NMP4-CT-2004-500101).
文摘This work deals with the study of optical and morphological properties of InGaAs/AlGaAs quantum dot(QD) structures grown by molecular beam epitaxy(MBE) . Photoluminescence(PL) emission energies,activation energies of PL quenching and QD sizes are studied as functions of the Al content in the AlyGa1-yAs confining layers(CL) . We show that the PL emission energy of In(Ga) As/AlyGa1-yAs QD structures increases with increasing y and that the sizes of InAs/AlyGa1-yAs QDs decrease with increasing y. By the comparison of the experimental results with those of an effective-mass model developed to calculate the QD fundamental transition energies,we show that the blueshift of emission energy has to be ascribed not only to the increase in barrier discontinuities that confine the carriers into QDs but even to effects related to changes of the QD morphology dependent on CL composition. Moreover,we show that the Al content in the barriers determines also the activation energy of thermal quenching of PL,which depends on the thermal escape of carriers from QD levels. These studies resulted in the preparation of structures with efficient light-emission in the 980 nm spectral window of interest for lightwave communications.
基金Project supported by the National Natural Science Foundation of China(Nos.61376077,61201046,61204081)the Beijing Natural Science Foundation(Nos.4132022,4122005)+1 种基金the Guangdong Strategic Emerging Industry Project of China(No.2012A080304003)the Doctoral Fund of Innovation of Beijing University of Technology
文摘The effect of drain-source voltage on A1GaAs/InGaAs PHEMTs thermal resistance is studied by experimental measuring and simulation. The result shows that A1GaAs/InGaAs PHEMTs thermal resistance presents a downward trend under the same power dissipation when the drain-source voltage （VDs） is decreased. Moreover, the relatively low VDS and large drain-source current （IDs） result in a lower thermal resistance. The chip-level and package-level thermal resistance have been extracted by the structure function method. The simulation result indicated that the high electric field occurs at the gate contact where the temperature rise occurs. A relatively low VDS leads to a relatively low electric field, which leads to the decline of the thermal resistance.
基金Project supported by the National Natural Science Foundation of China(No.61275107)
文摘90-nm T-shaped gate InP-based In_（0.52）Al_（0.48）As/In_（0.6）Ga_（0.4）As pseudomorphic high electron mobility transistors were designed and fabricated with a gate-width of 2×30 μm,a source-drain space of 2.5 μm,and a source-gate space of 0.75 μm.DC,RF and small-signal model characterizations were demonstrated.The maximum saturation current density was measured to be 755 mA/mm biased at V_（gs）=0.6 V and V_（ds）=1.5 V.The maximum extrinsic transconductance was measured to be 1006 mS/mm biased at V_（ds）=—0.1V and V_（ds）=1.5 V.The extrapolated current gain cutoff frequency and maximum oscillation frequency based on S-parameters measured from 0.5 to 110 GHz were 180 and 264 GHz,respectively.The inflection point（the stability factor k=1）where the slope from-10 dB/decade（MSG） to-20 dB/decade（MAG） was measured to be 83 GHz.The smallsignal model of this device was also established,and the S-parameters of the model are consistent with those measured from 0.5-110 GHz.
文摘A 50 MHz-1 GHz low noise and high linearity amplifier monolithic-microwave integrated-circuit （MMIC） for cable TV is presented.A shunt AC voltage negative feedback combined with source current negative feedback is adopted to extend the bandwidth and linearity.A novel DC bias feedback is introduced to stabilize the operation point,which improved the linearity further.The circuit was fabricated with a 0.15μm InGaAs PHEMT （pseudomorphic high electron mobility transistor） process.The test was carried out in 75Ωsystems from 50 MHz to 1 GHz.The measurement results showed that it gave a small signal gain of 16.5 dB with little gain ripples of less than±1dB.An excellent noise figure of 1.7-2.9 dB is obtained in the designed band.The IIP3 is 16 dBm, which shows very good linearity.The CSO and CTB are high up to 68 dBc and 77 dBc,respectively.The chip area is 0.56 mm^2 and the power dissipation is 110 mA with a 5 V supply.It is ideally suited to cable TV systems.
文摘采用普通接触曝光研制成栅长为 0 .2 5 μm的 Ga As基 In Al As/ In Ga As变组分高电子迁移率晶体管(MHEMT) ,测得其跨导为 5 2 2 m S/ m m,沟道电流密度达 4 90 m A/ mm,截止频率为 75 GHz,比同样工艺条件下Ga As基 In Ga P/ In Ga As PHEMT的性能有很大的提高 .对该器件工艺及结果进行了分析 ,提取了器件的交流小信号等效电路模型参数 ,并提出了进一步得到高稳定性、高性能器件的方法 .
