Growth of ternary InAlP and InGaP self-assembled quantum dots by metalorganic chemical vapor deposition

We report the characteristics of ternary InAlP and InGaP self-assembled quantum dots grown by metalorganic chemical vapor deposition. The structural and optical properties of these ternary quantum dots are compared with the characteristics of binary InP quantum dots grown under similar conditions. Because these ternary quantum dots have different bandgaps, strain, and composition compared to binary InP quantum dots, the ternary quantum-dot optical and physical properties are markedly different. The quantum-dot structures are grown uncapped (exposed QDs) and capped (embedded QDs) and characterized by atomic force microscopy (AFM) and photoluminescence (PL). InAlP quantum dots have higher densities and smaller sizes and InGaP quantum dots have smaller densities, as compared with InP quantum dots grown under similar conditions. Also, a random and broad size distribution is observed for InGaP quantum dots and the luminescence from InGaP dots is broader than for InP quantum dots.     

Design of broadband class-F power amplifier for multiband LTE handsets applications

A broadband class-F power amplifier for multiband LTE handsets applications is developed across 2.3-2.7 GHz. The power amplifier maintains constant fundamental impedance at the output matching circuit which is operating for broadband. The nearly zero of second harmonic impedance and nearly infinity of third harmonic impedance are found for highly efficient class-F PA. The harmonic control circuits are immersed into the broadband output matching for fundamental frequency. For demonstration, the PA is implemented in InGaP/GaAs HBT process, and tested across the frequency range of 2.3-2.7 GHz using a long-term evolution signal. The presented PA delivers good performance of high efficiency and high linearity, which shows that the broadband class-F PA supports the multiband LTE handsets applications.     

一种宽带的InGaP/GaAs HBT 再生频率分频器

A dynamic divide-by-two regenerative GaP/GaAs heterojunction bipolar transistors （HBTs） frequency divider （RFD） is presented in a 60-GHz-fT Intechnology. To achieve high operation bandwidth, active loads instead of resistor loads are incorporated into the RFD. On-wafer measurement shows that the divider is operating from 10 GHz up to at least 40 GHz, limited by the available input frequency. The maximum operation frequency of the divider is found to be much higher than fT/2 of the transistor, and also the divider has excellent input sensitivity. The divider consumes 300.85 mW from 5 V supply and occupies an area of 0.47 × 0.22 mm^2.     

Large signal RF power transmission characterization of InGaP HBT for RF power amplifiers

The large signal RF power transmission characteristics of an advanced InGaP HBT in an RF power amplifier are investigated and analyzed experimentally. The realistic RF powers reflected by the transistor, transmitted from the transistor and reflected by the load are investigated at small signal and large signal levels. The RF power multiple frequency components at the input and output ports are investigated at small signal and large signal levels, including their effects on RF power gain compression and nonlinearity. The results show that the RF power reflections are different between the output and input ports. At the input port the reflected power is not always proportional to input power level; at large power levels the reflected power becomes more serious than that at small signal levels, and there is a knee point at large power levels. The results also show the effects of the power multiple frequency components on RF amplification.     

Hydrogen-induced transient effect in carbon-doped InGaP hetero-junction bipolar transistors

The transient effect on the current gain of InGaP hetero-junction bipolar transistors was studied. It was found that this transient effect was caused by hydrogen and eliminated after three or more cycles of thermal annealing at 250 °C in nitrogen. A model based on the carbon-hydrogen complex dissociation by thermal anneal is proposed to explain this observation.     

Photoluminescence analysis of InGaP top cells for high-efficiency multi-junction solar cells

A way of evaluate the minority-carrier lifetime by using photoluminescence (PL) measurement is proposed which includes self-absorption. The room-temperature PL intensity is analyzed theoretically for bulk crystals and a device with n⁺-p junction configuration, based on a one-dimensional model. Photoluminescence analysis of In_0.5Ga_0.5P solar cells grown on GaAs and Si substrates by MOCVD (metal organic vapor deposition) have been carried out and compared with the properties of the In_0.5Ga_0.5P solar cells. By improving minority-carrier lifetime, high-efficiency In_0.5Ga_0.5P cells on GaAs substrates with an efficiency of 18.5% have been made.     

A 3.4-3.6 GHz power amplifier in an InGaP/GaAs HBT

报道了基于InGaP/GaAs HBT工艺的3.4-3.6GHz功率放大器芯片的设计。针对片外和片内寄生因素引起的谐振点偏移、匹配变差、增益降低等问题,通过优化设计片外匹配电路以及设计输入匹配的片外调整电路,最终取得了较高的增益以及良好的匹配状态。电路测试结果为：在Vcc为4.3V以及Vbias=3.3V下,3.4GHz处的1dB压缩点输出功率达到27.1dBm以上,相应的PAE为25.8%,二次谐波和三次谐波抑制比分别达到了-64dBc和-51dBc。在3.4-3.6GHz频段内,增益大于28dB, S11<-12.4dB,S22<-7.4dB,达到了设计要求。     

A 3.4-3.6 GHz power amplifier in an InGaP/GaAs HBT

This paper presents a 3.4-3.6 GHz power amplifier（PA） designed and implemented in InGaP/GaAs HBT technology.By optimizing the off-chip output matching network and designing an extra input-matching circuit on the PCB,several problems are resolved,such as resonant frequency point migration,worse matching and lower gain caused by parasitics inside and outside of the chip.Under V_cc = 4.3 V and V_bias = 3.3 V,a P_1dB of 27.1 dBm has been measured at 3.4 GHz with a PAE of 25.8%,the 2nd and 3rd harmonics are -64 dBc and -51 dBc,respectively. In addition,this PA shows a linear gain more than 28 dB with S₁₁<-12.4dB and S₂₂<-7.4 dB in 3.4-3.6 GHz band.     

Control of threshold voltage and improved subthreshold swing in enhancement-mode InGaP/InGaAs metal-oxide-semiconductor pseudomorphic high-electron-mobility transistor

The InGaP/InGaAs metal-oxide-semiconductor pseudomorphic high-electron-mobility transistor (MOS-PHEMT) with an oxidized GaAs gate by liquid phase oxidation (LPO) is demonstrated. With the help of the LPO, the threshold voltage (V_th) can be shifted positively to 0.07 V, and enhancement-mode MOS-PHEMT is fabricated. The device with a gate metal of 1 × 100 μm² shows a maximum transconductance of 171 mS/mm at V_DS = 5 V and a maximum drain current density of 182 mA/mm at V_GS = 2 V. It also exhibits a lower leakage current and an improved subthreshold swing compared to the referenced Schottky-gate InGaP/InGaAs PHEMT.     

基于InGaP/GaAs HBT的10Gbps跨阻放大器

采用InGaP/GaAs HBTs设计并实现了传输速率为10Gbps的跨阻放大器.在电路设计上采用两级放大器级联的形式以提高跨阻增益,在第一级采用了cascade结构,第二级采用了cherry hooper结构以提高电路的带宽和稳定性.测试结果表明,跨阻增益为40dB·Ω and 3dB带宽为10GHz.