The electrical properties of ion-implanted GaAs FET channels
are investigated by two methods. First, the channel current (I) as
a function of voltage (V) is examined at different temperatures and
using different voltage ramp rates. The standard FET I-V curve,
which can be observed on a commercial curve tracer, is...
The photoresponse behavior of semi-insulating GaAs is
investigated. The photocarrier lifetime is discussed and
the influence of surface and contact recombination is
taken into account. Photocurrent-voltage characteristics
have been measured and a mechanism for the gain in terms
of space charge amplification and avalanching is suggested.
The influence of deep...
The optical and electrical characteristics of semi-insulating GaAs photoconductive detectors made with ohmic and Schottky contacts are studied in this thesis. Current - voltage measurements are made both in the dark and under varying power levels of HeNe laser (6328 Å) illumination. DC photocurrent gain is then calculated as a...
The characteristic of the subthreshold current in a
GaAs MESFET exhibits a negative exponential function with
Vgs. After studying the behavior of this current in this
region over a range of temperature and drain bias voltages,
a subthreshold current model was developed. The model was
implemented in a circuit simulation...
Different gate length (0.5 μm 16 μm) Al GaAs/GaAs and
AIGaAs /InGaAs High Electron Mobility Transistors were electrically
characterized in order to compare the room temperature DC device
performance with one-dimensional device models. Model parameters
such as the channel mobility and source/drain series resistances are
extracted from independent measurement of...
This thesis reports on the crystal growth, fabrication,
modeling and performance of Graded Index-Separate Confinement
Heterostructure laser diodes which contain pseudomorphic InGaAs as the
active region material. Laser epitaxial layers were grown with
different indium mole-fractions, and a constant InGaAs layer thickness
of 10 nm, on both sides of the...
GaAs MESFETs are widely used in high speed integrated circuits (ICs) and
microwave circuits. Due to the materials and processing methods used in GaAs
MESFET fabrication, deep level traps in the substrate materials have a strong influence
on device performance.
In this work we used the drain current transient characterization...
A complete Gallium Arsenide Metal Semiconconductor
Field Effect Transistor (GaAs MESFET) model including deep-level
trap effects has been developed, which is far more
accurate than previous equivalent circuit models, for high-speed
applications in linear integrated circuit design.
A new self-backgating GaAs MESFET model, which can
simulate low frequency anomalies, is...
The semiconductor gallium arsenide (GaAs) has many potential
advantages over the more widely used semiconductor silicon (Si).
These include higher low field mobility, semi-insulating substrates,
a direct band-gap, and greater radiation hardness. All these
advantages offer distinct opportunities for implementation of new
circuit functions or extension of the operating conditions...
High speed photodetectors are a necessary element in
broad band digital and analog optical communication systems.
In this thesis easily integrable planar high speed
photodetectors made on undoped semi-insulating (SI) GaAs
substrates are modeled and tested. The fabrication process
of the detectors is fully compatible with GaAs
metal-semiconductor field effect...
A study of deep levels of the emitter region of a
heterojunction bipolar transistor is investigated using deep
level transient spectroscopy (DLTS), deep level admittance
spectroscopy (DLAS), thermally stimulated capacitance
(TSCAP), and capacitance-voltage (C-V) profiling. The DX
center, with an activation energy of 0.45 eV, is the only
deep level...
This thesis reports on the growth and characterization of p-type
pseudomorphic A1GaAs /InGaAs /GaAs modulation doped field effect transistor
(MODFET) structures. A series of different p-type MODFET structures were grown
with a systematic variation of the indium mole fraction and quantum well width of
the InGaAs channel region. Extensive characterization...
Present day data processing technology requires very high speed signal processing and data conversion rates. One such application which requires high speed is switched capacitor circuits used in Sigma-Delta modulators. A major active component of switched capacitor circuits is the monolithic operational amplifier(opamp). Because of the relatively poor speed performance...