B. Brar

InAs/AlSb HEMT and Its Application to Ultra-Low-Power Wideband High-Gain Low-Noise Amplifiers

Two antimonide-based compound semiconductor (ABCS) microstrip monolithic microwave integrated circuits (MMICs), i.e., single- and three-stage ultra-low-power wideband 0.3-11-GHz low-noise amplifiers (LNAs) using 0.1-mum gate-length InAs/AlSb metamorphic high electron-mobility transistors (HEMTs), have been fabricated and characterized on a GaAs substrate. The single-stage wideband LNA demonstrated a typical associated gain of 16 dB (0.3-11 GHz) with less than a 1.7-dB noise figure (2-11 GHz) at 5-mW dc power dissipation, and the three-stage wideband LNA demonstrated a typical associated gain of 30 dB (0.3-11 GHz) with less than a 2.6-dB noise figure (2-11 GHz) at 7.5-mW dc power dissipation. We believe these wideband LNA MMICs demonstrate the lowest dc power consumption with the highest gain-bandwidth product of any MMIC to date. These results demonstrate the outstanding potential of ABCS HEMT technology for ultra-low-power wideband applications

Transistor and circuit design for 100-200 GHz ICs

Compared to SiGe, InP HBTs offer superior electron transport properties but inferior scaling and parasitic reduction. Figures of merit for mixed-signal ICs are developed and HBT scaling laws introduced. Device and circuit results are summarized, including a simultaneous 450 GHz f/sub /spl tau// and 490 GHz f/sub max/ DHBT, 172-GHz amplifiers with 8.3-dBm output power and 4.5-dB associated power gain, and 150-GHz static frequency dividers (a digital circuit figure-of-merit for a device technology). To compete with advanced 100-nm SiGe processes, InP HBTs must be similarly scaled and high process yields are imperative. Described are several process modules in development: these include an emitter-base dielectric sidewall spacer for increased yield, a collector pedestal implant for reduced extrinsic C/sub cb/, and emitter junction regrowth for reduced base and emitter resistances.

An ultra-low power InAs/AlSb HEMT W-band low-noise amplifier

An antimonide-based compound semiconductor (ABCS) microstrip MMIC, a W-Band low-noise amplifier using 0.2-μm gate length InAs/AlSb metamorphic HEMTs, has been fabricated and characterized on a 50 μm GaAs substrate. The compact 1.2 mm 2 five-stage W-band LNA demonstrated a 3.9 dB noise-figure at 94 GHz with an associated gain of 20.5 dB. The measured dc power dissipation of the ABCS LNA was an ultra-low 1.2mW per stage, or 6.0 mW total which is less than one-tenth the dc power dissipation of a typical equivalent InGaAs/AlGaAs/GaAs HEMT LNA. Operation with degraded gain and noise figure at 3.5 mW total de power dissipation is also verified. These results demonstrate the outstanding potential of ABCS HEMT technology for mobile and space-based millimeter-wave applications.

Ultra high frequency static dividers > 150 GHz in a narrow mesa InGaAs/InP DHBT technology

A static frequency divider with a maximum clock frequency >150 GHz was designed and fabricated in a narrow mesa InP/In/sub 0.53/Ga/sub 0.47/As/InP DHBT technology. The divider operation is fully static, operating from f/sub dk/ = 3 GHz to 152.0 GHz while dissipating 594.7 mW of power in the circuit core from a -4.07 V supply. The circuit employs single-buffered emitter coupled logic (ECL) and inductive peaking. The transistors have an emitter junction width of 0.5 /spl mu/m and a 3.0 collector-to-emitter area ratio. A microstrip wiring environment is employed for high interconnect density, and to minimize resonances and impedance mismatch at frequencies >100 GHz.

InAs/AlSb HFETs with f τ and f max above 150 GHz for low-power MMICs

Very low-power InAs/AlSb HFETs with excellent RF performance are reported. These metamorphic HFETs on GaAs substrates combine high microwave g/sub m/ of at least 1.1 S/mm with low parasitic resistances to offer simultaneous measured f/sub /spl tau// and f/sub max/ values of 160 GHz for both figures of merit. This performance is obtained at a drain bias voltage of only 0.35 V for an HFET with a 0.25-/spl mu/m gate length. The high current gain (f/sub /spl tau//) is attributable to the improved charge control due to scaling of the barrier thickness to 180 /spl Aring/. The maximum power gain (f/sub max/) depends on both g/sub m/ and the HFET output conductance, which is fundamentally limited by the low breakdown voltage gap of the InAs channel (E/sub g/ = 0.36 eV).

Resonant tunneling circuit technology: has it arrived?

A three-dimensional large-scale integration (LSI) process for fabrication of resonant tunneling diodes and heterojunction field-effect transistors on InP has been demonstrated, combining two of todays fastest semiconductor devices. Demonstrations of this technology now include multigigahertz digital and mixed-signal circuits and ultralow power SRAM circuits; 25 to 100 GHz circuits are clearly in range for this technology.

Low-voltage, high-performance InAs/AlSb HEMTs with power gain above 100 GHz at 100 mV drain bias

Ultra-low power circuits require transistors with usable RF gain at low bias voltages and currents. In the present paper, we report 100 nm gate-length InAs/AlSb HEMTs with f/sub /spl tau// and f/sub max/ both exceeding 100 GHz at a mere 100 mV of drain bias. The devices also show excellent peak value for f/sub /spl tau// of 235 GHz and, to the best of our knowledge, a record f/sub max/ of 235 GHz at a higher drain bias of 300 mV.

Deep submicron InP DHBT technology with electroplated emitter and base contacts

We report the development of a wide bandwidth InP double heterojunction bipolar transistor technology that utilizes novel electroplating processes to form the emitter and base contacts. The technology enables the fabrication of HBTs with deep submicron emitter-base junction dimensions and self-aligned base ohmic contacts. Using this technology, HBTs have been fabricated with emitter junction widths scaled to 0.25 /spl mu/m. These devices demonstrated peak f/sub /spl tau// and f/sub max/, values of over 300 GHz. The transistors also support high current density operation (J/sub E/>7 mA//spl mu/m/sup 2/) and have a low collector-base capacitance to collector current ratio (C/sub cb//I/sub c//spl sim/0.55 ps/V), an important parameter for digital logic speed.

Advanced InP DHBT process for high speed LSI circuits

We report on the development of an advanced InP double heterojunction bipolar transistor (DHBT) technology that utilizes electroplated device contacts and dielectric sidewall spacers to form a self-aligned base-emitter junction. These processes permit aggressive scaling of the transistor, while achieving high levels of yield and manufacturability. HBTs with 0.5 mum emitter junction widths have been demonstrated with an ft/fmax of 405/390 GHz and a common-emitter breakdown voltage BVCEO >4 V. Large-scale direct digital synthesizer (DDS) circuits have been fabricated operating at clock rates up to 24 GHz.

Ultra-Low-Power Wideband High Gain InAs/AlSb HEMT Low-Noise Amplifiers

Two antimonide-based compound semiconductor (ABCS) microstrip MMICs, single-stage and three-stage ultra-low-power wideband 0.01-11 GHz low-noise amplifiers using 0.1-mum gate length InAs/AlSb metamorphic HEMTs, have been fabricated and characterized on a GaAs substrate. From 0.3-11 GHz, the single-stage wideband LNA demonstrated a typical associated gain of 16 dB with less than 1.7 dB noise figure (2-11 GHz) at 5mW DC power dissipation, and the three-stage wideband LNA demonstrated a typical associated gain of 30 dB with less than 2.6 dB noise figure (2-11 GHz) at 7.5mW DC power dissipation. We believe these low noise amplifier MMICs demonstrate the lowest DC power consumption with the highest gain-bandwidth product of any MMIC to date. These results demonstrate the outstanding potential of ABCS HEMT technology for ultra-low-power wideband applications