InP DHBT Amplifiers and Circuit Packaging up to Submillimeter-Wave Frequencies
This thesis treats the design and characterization of amplifiers operating up to
submillimeter-wave frequencies and packaging of such circuits into waveguide
modules. The circuits use an advanced indium phosphide (InP) double heterojunction
bipolar transistor (DHBT) process with a multilayer back-end. Several amplifiers in
the frequency range from 80 to 300 GHz with state-of-the-art performance are
presented. The amplifiers utilize different transistor configurations: common-emitter,
common-base, and cascode. One of the amplifiers, a five-stage common-emitter
circuit, demonstrates 24 dB gain at 255 GHz with a minimum noise figure of 10.4 dB
at 265 GHz. This is the lowest reported noise figure for amplifiers in bipolar
technology operating at such high frequencies. Circuits like these can find
applications in a variety of systems such as wireless high data-rate communication
links and high-resolution imaging systems.
Furthermore, amplifiers with the highest reported bandwidths for transistorbased
amplifiers, regardless of transistor technology, are presented in this thesis.
These amplifiers use distributed topologies to achieve such wideband characteristics.
The widest bandwidth is reached with a 2-cascaded distributed amplifier that has an
average gain of 16 dB from 2 to 237 GHz, i.e., a bandwidth of 235 GHz.
A potential problem with integrated circuits with a large front-side metallization
is the risk of resonating parasitic modes within the circuit substrate. The influence of
such resonances is studied through simulations and measurements of passive and
active circuits. It is shown that a resistive Si carrier underneath the circuit is an
effective method to eliminate the effects of parasitic substrate modes.
The high operating frequencies of these circuits make the development of a
functional packaging method challenging. In this thesis, two waveguide InP DHBT
amplifier modules operating in the frequency bands 150‒260 GHz and 210‒300 GHz
using a novel waveguide-to-circuit transition realized in membrane technology are
demonstrated. It is the first published results on InP DHBT amplifier modules
operating at these high frequencies. Furthermore, membrane technology has not been
used in packaging of transistor-based integrated circuits before. One of the amplifier
modules is measured at a temperature of 100 K. The noise temperature of the module
is reduced from 3500 K at room temperature to 1800 K when cooled. This is the first
reported characterization of an InP DHBT circuit at cryogenic temperature.
multiple layer interconnect
double heterojunction bipolar transistor (DHBT)
distributed amplifier (DA)
low-noise amplifier (LNA)