Título
Implantación y difusión de impurezas en silicio de alto índice cristalino
Autor
MIGUEL CASTRO LICONA
Colaborador
FRANCISCO JAVIER DE LA HIDALGA WADE (Asesor de tesis)
PEDRO ROSALES QUINTERO (Asesor de tesis)
Nivel de Acceso
Acceso Abierto
Materias
Resumen o descripción
In this work, the diffusion mechanisms of both boron and phosphorus dopants are
analyzed when they are diffused or ion-implanted and activated/diffused in high-index
silicon substrates. Si(1 1 4) and Si(5 5 12) wafers are reported as highly promising
substrates for the development of novel quantum structures especially for MOS
devices. In order to obtain the final dopant distribution an electrochemical profiler was
utilized. Because it is well known the lack of reported experimental data regarding the
doping mechanism in these high-index silicon substrates, Si(0 0 1) and Si(1 1 1)
substrates were utilized as reference. The experimental work was conducted varying
the following parameters: temperature, doses, energy, tilt angle, silicon oxide masking
film thickness, ambient and activation method; the thermal activation/diffusion of the
impurities was specially evaluated because they influence in the final distribution of
dopants. The doping profile of each experimental condition was extracted and
discussed in terms of the anomalous effects: OED (Oxidation-Enhanced Diffusion),
TED (Transient Enhanced Diffusion), and ion channeling. A test chip was fabricated
to measure process and device parameters which were related to the profiles
measured. The MOS (Metal-Oxide-Semiconductor) transistor performance fabricated
in the high index silicon was evaluated and compared to those fabricated in the low
index silicon substrates. From the results presented in this work, we can state:
-If the diffusion process is not conducted under oxidation, then diffusivity (D) in
high index silicon substrate is independent on the crystal orientation; however,
under oxidation conditions, it process becomes a strong function of crystal
orientation and exhibits the tendency: D(0 0 1)<D (1 1 4) <D(5 5 12)<D (1 1 1) .
-Any anomalous effect can be observed when diffusion process is conducted
under high temperature for very long time.
- If silicon oxide masking film is thicker than 600 Å, then channeling is
minimized. This result is quite interesting since it reveals that it is possible,
under certain conditions, to perform implants with a tilt angle=0°. Despite that
Si(001) is normally tilted at 7° for ion implantation (to prevent the channeling),
our results demonstrated that under certain conditions (implantation through a
thick dioxide), it is possible to implant phosphorus with a tilt angle=0° obtaining
a poor ion channeling. This is an important technological result since it could
lea
Editor
Instituto Nacional de Astrofísica, Óptica y Electrónica
Fecha de publicación
abril de 2008
Tipo de publicación
Tesis de doctorado
Versión de la publicación
Versión aceptada
Recurso de información
Formato
application/pdf
Idioma
Inglés
Audiencia
Estudiantes
Investigadores
Público en general
Sugerencia de citación
Castro-Licona M
Repositorio Orígen
Repositorio Institucional del INAOE
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