Study of transport and operational parameters for III-V semiconductor radiation detectors

Doctoral Dissertation uoadl:1309061 667 Read counter

Unit:
Τομέας Φυσικής Συμπυκνωμένης Ύλης
Library of the School of Science
Deposit date:
2013-05-28
Year:
2013
Author:
Θεωνάς Βασίλειος
Dissertation committee:
Παπαϊωάννου Γεώργιος Αν. Καθ. (κύριος επιβλέπων), Τριμπέρης Γεώργιος Καθ., Γιόκαρης Νικόλαος Καθ.
Original Title:
Μελέτη παραμέτρων μεταφοράς και λειτουργίας ανιχνευτών ημιαγωγών III-V
Languages:
Greek
Translated title:
Study of transport and operational parameters for III-V semiconductor radiation detectors
Summary:
Semiconductor radiation detectors are an important example of technological
advances that have arisen from the research of semiconductor physics in the
last 50 years. Aside from the plethora of research and technological
applications, their use extends now even in commercial applications available
to the general public. This research field most important contribution is
related to new techniques in imaging - diagnostic medicine.
The PhD thesis aims to meaningful exploration of the basic parameters governing
the operation of radiation detectors, with particular emphasis on semiconductor
detectors of EPT III-V groups and aims to study the transfer parameters and
their impact on operating characteristics of these devices.
We modeled the function of a typical planar radiation detector manufactured by
(SI) GaAs, i.e a compound semiconductor widely used in the field of radiation
detector devices (a typical semiconductor of groups III-V). The study and
evaluation of transport parameters of a planar semiconductor radiation detector
comprises two components: a) combinational simulations using models developed
by the author with available Monte Carlo statistical models developed by
universities and research institutes and b) experimental evaluation of
detectors (manufactured by the Institute of Electronic Structure & Laser FORTH,
Crete) functional characteristics.
The Developed algorithms calculate: a) during dark state, the spatial
distribution of potential, electric field, intrinsic electric field,
concentration, velocity and Quasi Fermi levels of electrons and holes, space
charge density and the extend of the active region of the detector b) during
the ionizing radiation excited state, the characteristics of the current pulse
response a detector operated in current or pulse mode.
Simulation results obtained under various excitations (ionizing radiation) feed
to a methodology developed that produces multi-parametric curves suitable for
incorporation into dia-parametric techniques that trend to be necessary in
order to improve the performance of semiconductor detector devices.
Using simulation procedure, we estimated the influence of a (SI) GaAs detector’
s contacts thickness to the device response and experimentally confirmed that
contacts thickness differentiate the detector’s output pulse due to the
contribution of Secondary Electron Emission from irradiated contact to the
semiconductor.
Finally we studied the parasitic charging phenomenon of insulating thin layers
contained in semiconductor radiation detectors and in RF MEMS switches, while
irradiated by ionizing radiation. Simulation results indicate that parasitic
charge accumulated in the insulating film is attributed to a dynamic
equilibrium procedure affecting the Secondary Electrons Emission from the
irradiated contact to the insulator and the reverse process, and its value
depends on the type and density of the insulator and the type - energy of
ionizing radiation.
Keywords:
Semiconductor radiation detectors, Electromagnetic and charged particles ionizing radiation detector simulation, Contacts effect on (SI) GaAs radiation detectors response , Energy resolution enhancing dia-paremetric techniques, RF MEMS dielectric charging due to ionizing radiation
Index:
Yes
Number of index pages:
0-8 έως 0-31
Contains images:
Yes
Number of references:
269
Number of pages:
474
document.pdf (34 MB) Open in new window