3.9 ps SiGe HBT ECL ring oscillator and transistor design for minimum gate delay

We show empirical results that demonstrate the effect of high performance SiGe HBT design parameters on the minimum gate delay of an ECL ring oscillator. SiGe HBT devices with a high f/sub MAX/ (338 GHz) and a low f/sub T/ (180 GHz) achieve a minimum delay of 3.9 ps, which to our knowledge is the lowest reported delay for a silicon based logic gate. Compared to the extracted (extrapolated) f/sub T/ and f/sub MAX/, a simple figure of merit proportional to /spl radic/f/sub T//R/sub B/C/sub CB/ with R/sub B/ and C/sub CB/ extracted from S-parameter measurement is best correlated to the minimum gate delay.     

3.21 ps ECL gate using InP/InGaAs DHBT technology

A new circuit configuration for an emitter-coupled logic (ECL) gate that can reduce propagation delay time has been demonstrated. Nineteen-stage ring oscillators were fabricated using InP/InGaAs double-heterojunction bipolar transistors (DHBTs) with cutoff frequency f/sub T/ and maximum oscillation frequency f/sub max/ of about 232 and 360 GHz, respectively, to evaluate the speed performance of the proposed ECL gate. The minimum propagation delay is 3.21 ps/gate. The proposed ECL gate is about 8% faster than the conventional ECL gate.     

Submicron AlInAs/InGaAs HBT with 160 GHz fT at 1 mAcollector current

We have demonstrated a submicron heterojunction bipolar transistor (SHBT) with a unity current gain cutoff frequency (f_t) of 160 GHz at the very low current level of 1 mA. The AlInAs/InGaAs SHBT has a thin collector and uses stepper lithography with 0.1 μm registration accuracy to reduce the parasitic elements that typically limit the performance of small transistors. The same device has 100 GHz f_t at 200 μA. The result substantially improves upon the cutoff frequency of submicron compound semiconductor devices. The technology is appropriate for high speed, low power, high-density circuits     

5 V, DC-12 GHz InP/InGaAs HBT amplifier

An InP/InGaAs HBT cascode amplifier operating from a single 5 V power supply is described. The circuit has a DC gain of 17.2 dB and a -3 dB frequency point of 12.3 GHz. This results in a gain-bandwidth product in excess of 90 GHz. The frequency response of the amplifier remains constant if the power supply voltage is as low as 4 V.<>     

InP/InGaAs HBT的频率特性分析

频率特性是异质结双极型晶体管(HBT)设计中应首先考虑的因素,而fT,fmax则是HBT最主要的频率性能指标.首先基于InP/InGaAs HBT器件的物理结构构建了小信号等效电路模型,对该模型进行了理论分析,随后基于提取的有效参数结果,对该等效电路模型的频率特性进行了详细的计算和仿真,分析了影响fT,fmax的一些主要因素,得出的结论对于InP/InGaAs HBT的设计制作和性能优化具有一定的指导作用.     

Optimization of the spacer layer thickness in AlInAs/InGaAs/InP MODFETs

The effects of spacer layer thickness variations on single atomic planar doped (APD) AlInAs/InGaAs modulation doped field effect transistors grown by solid source molecular beam epitaxy have been studied and characterized. The thickness of the AlInAs spacer layer was varied between 0 and 100Å. Room temperature Hall measurements found the mobility exhibited an exponential relationship ranging from 6500 to 10800 cm²/Vs. The sheet charge varied linearly from 3.46 × 10¹² cm^?2 to 2.24 × 10¹² cm^?2. An optimum spacer layer thickness based on maximum channel conductance was found to be 40Å with a mobility of 9600 cm²/Vs and a sheet charge of 3.0 × 10¹² cm^?2. The loss of mobility due to remote ion scattering was examined. This loss was related to the distribution of the Si atoms in the atomic planar doped layer in order to obtain the standard deviation of the interface. This relationship will allow various growth parameters, such as substrate temperature, growth rate, and V/III ratio to be altered to determine the optimum conditions independent of the growth chamber used to create the structures.     

InP/InGaAs HBT高频放大器稳定性分析

根据异质结双极晶体管(HBT)的实际结构提出高频小信号电路模型,以此模型用于共射放大电路为出发点,从理论上阐明了高频放大电路产生不稳定的原因,分析了端接电阻的稳定方法,借助matlab快速确定出稳定电阻的取值范围,其理论计算与仿真有很好的一致.     

Transfer of sub-5 ps electrical test pulses to coplanar and coaxialelectronic devices

A technique that allows for the transfer of 3.3 (4.9) picosecond voltage pulses to electronic devices with coaxial (coplanar) transmission line geometry is presented. Using this method, electronic circuits can be characterised at frequencies well above 100 GHz     

An open loop compensation technique for reducing supply sensitivity of CML ring oscillator

Physical layer security has emerged as a promising approach to strengthen security of wireless communications. Particularly, extracting secret keys from channel randomness has attracted an increasing interest from both academic and industrial research groups. In this paper, we present a complete implantation of a secret key generation (SKG) protocol which is compliant with existing widespread Radio Access Technologies. This protocol performs the quantization of the channel state information, then information reconciliation and privacy amplification. We also propose an innovative algorithm to reduce the correlation between quantized channel coefficients that significantly improves the reliability and the resilience of the complete SKG scheme. Finally we assess the performance of our protocol by evaluating the quality of secret keys generated in various propagation environments from real single sense LTE signals, and real single and dual sense WiFi signals.     

Comparison Between the Dynamic Performance of Double- and Single-Gate AlInAs/InGaAs HEMTs

The static and dynamic behavior of InAlAs/InGaAs double-gate high-electron mobility transistors (DG-HEMTs) is studied by means of an ensemble 2-D Monte Carlo simulator. The model allows us to satisfactorily reproduce the experimental performance of this novel device and to go deeply into its physical behavior. A complete comparison between DG and similar standard HEMTs has been performed, and devices with different gate lengths have been analyzed in order to check the attenuation of short-channel effects expected in the DG-structures. We have confirmed that, for very small gate lengths, short-channel effects are less significant in the DG-HEMTs, leading to a better intrinsic dynamic performance. Moreover, the higher values of the transconductance over drain conductance ratio g_m /g_d, and, especially, the lower gate resistance R_g also provide a significant improvement of the extrinsic f_max.     

Analytic model for the post-breakdown conductance of sub-5-nm SiO/sub 2/ gate oxides

A new model for the post-breakdown conductance of ultrathin gate oxides based on the generalized diode equation is presented. The model is expressed in terms of the Lambert W function, that is, the inverse of the function w/spl rarr/we/sup w/. We show that this alternative formulation improves a previous one, the quantum point contact model, especially in the low bias range, where the role played by the semiconductor electrodes cannot be overlooked. The practical implementation of the proposed equations is discussed.     

A series of InGaP/InGaAs HBT oscillators up to D-band

In this paper, the development of a series of fixed-frequency heterojunction bipolar transistor (HBT) oscillators from the W- to D-bands is reported. The oscillators are designed based on feedback theory with a small-signal equivalent circuit. This design method enables the achievement of high-output-power oscillators for the management of the power that is generated at the current source inside the HBT. We use a 1 μm×10 μm single-emitter InGaP/InGaAs HBT as an active device for each oscillator, and 50-Ω coplanar waveguides as transmission lines and resonators. Emitter output topology is adopted to reduce the chip size. The series of oscillators achieve the oscillation frequency of 74.8-146.7 GHz. To our knowledge, the 146.7-GHz fundamental oscillation frequency is the highest oscillation frequency achieved thus far using InGaP/InGaAs HBT technology. The output power of the 146.7-GHz oscillator is -18.4 dBm. The chip size of the oscillator is 731 μm×411 μm     

Dependence of current-gain cutoff frequency on gate length in submicron GaInAs/AlInAs MODFETs

Investigates the gate length (L/sub g/) dependence of the current-gain cutoff frequency f/sub T/ in lattice-matched GaInAs/AlInAs MODFETs. The transconductance is found to be relatively insensitive to gate length in this submicron regime, while the f/sub T/ increases with decreasing gate length due to reduced capacitance as dictated by the charge control model. An effective saturation velocity of 1.3*10/sup 7/ cm/s is deduced from the f/sub T/-L/sub g/ dependence. A maximum f/sub T/ of 112 GHz is measured on an L/sub g/=0.15 mu m device, limited mainly by parasitic charge in the AlInAs.<>     

Measurement of base and collector transit times in thin-base InGaAs/InP HBT

The influence of base thickness reduction on performances of heterojunction bipolar transistors (HBTs) is examined. HBT structures are grown, with a base thickness in the range 25-65 nm and doping concentration from 3/spl times/10/sup 19/ to 6/spl times/10/sup 19/ at/cm/sup 3/. Base transit time is accurately extracted from total base-collector transit time, and described using a simple drift-diffusion approach. This model, however basic, shows very good agreement with measurements when usual parameter values are used. A 0.13-ps transit time reduction is measured when thinning the base from 65 to 25 nm. The thinnest base structure presents a 0.08 ps transit time, allowing a 250 GHz f/sub t/ operation at 270 kA/cm/sup 2/ emitter current density.     

Bias-stress-induced increase in parasitic resistance of InP-based InAlAs/InGaAs HEMTs

The reliability of InP-based HEMTs is studied, focussing on how it is affected by the doped layer material and gate recess structure. Bias-and-temperature stress tests reveal that fluorine-induced donor passivation in the recess region, formed adjacent to the gate electrode, causes the source resistance (R_s) to increase at large drain bias voltages. The increase in R_s can be prevented by using InP or InAlP as the carrier supply layer material instead of InAlAs. On the other hand, the increase in the drain resistance (R_d) does not depend on the material of the carrier supply layer, which suggests that a mechanism different from that in the case of R_s should be considered. It is also found that a deep gate recess suppresses the increase in R_d after long-term stressing.     

Demonstration of an InGaAsP/InGaAs multiquantum well active-gratingsurface-emitting amplifier

The design and operating characteristics of an InGaAsP/InGaAs strained-layer multiquantum-well active-grating surface-emitting amplifier operating at a wavelength of 1.6 μm are reported. Single-wavelength operation was obtained with 25-dB suppression of amplified spontaneous emission at 150-mW peak power output with a differential quantum efficiency of 24%. This result verifies earlier theoretical predictions that a power output per unit length of ~1 W/cm is feasible     

Admittance spectroscopy of ring diode InGaAs/InAlAs/InP quantum-well structures

The admittance of ring planar diode Au/InGaAs/InP and Au/InGaAs/InAlAs heteronanostructures on i-InP has been studied. The structures are constituted by a silicon ??-doped layer and an InGaAs quantum well (QW) in InP or InAlAs epitaxial layers. An analysis of the capacitance-voltage and conductance-voltage characteristics yielded distribution profiles of the electron concentration and mobility in the vicinity of the QW and ??-doped layer. It is shown that lowering the temperature leads to an increase in the electron concentration and mobility in the QW.     

Self-compensation of short-channel effects in sub-0.1-μmInAlAs/InGaAs MODFETs by electrochemical etching

We show that by making full use of the features of electrochemical etching in InAlAs/InGaAs heterostructures, deep gate grooves with small side etching can be fabricated. The most important advantage of this technology is that the vertical etching in the small gate openings will be remarkably enhanced by a self-organized process. Therefore the electrochemical etching provides a what we call “self-compensation” of the short channel effects. The effectiveness of this technology is evidenced by the excellent performance combined with the alleviation of the threshold-voltage shift and suppression of transconductance degradation in MODFET's with gate lengths below 0.1 μm     

Demonstration of passive Q-switching in multiquantum well InGaAs/AlGaInAs diode laser

The first passive Q-switched operation is reported of an InGaAs-AlGaInAs diode laser with a frequency repetition ranging from 1 to 2.5 GHz at the emitting wavelength of 1.58 /spl mu/m. This material is important as a thermally stable alternative to InGaAsP based laser systems operating around 1.5 /spl mu/m.