Class1_Slides

Class1_Slides - Physical Electronics EE.338 Steve Cronin...

Info iconThis preview shows pages 1–22. Sign up to view the full content.

View Full Document Right Arrow Icon
Steve Cronin University of Southern California Electrical Engineering - Electrophysics Physical Electronics EE.338
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chapter 1: Crystal Structure
Background image of page 2
Amorphous Materials (a) – solids made up of atoms with no long or short range order. Used as insulators in ICs. 3 Types of Solids Polycrystalline Materials (b) – solids made up of small crystalline regions or grains but no long range order. Polycrystalline materials now finding use in IC’s as gates in MOSFETs Crystalline Materials (c) – atoms of solid are arranged in a regular, 3D pattern with the same periodicity in the pattern in all regions.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Lattices and Unit Cells 12 rn a n b =+ rrr Lattice vectors define the structure. 123 a n b n c =++ rrrr 2D lattice 3D lattice The unit cell of a lattice is an array of points in space that can be translated by a lattice vector to produce the lattice. (Unit cells of lattices are not unique!) A 3D primitive unit cell. Lattices are periodic arrays of points in space. Primitive unit cells are smallest volume cells that can be used to replicate the lattices.
Background image of page 4
Periodic Structures (crystals)
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Primitive Unit Cells Even primative unit cells are not unique.
Background image of page 6
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 8
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 10
5 Bravais Lattices (2D) Bravais lattice , named after Auguste Bravais, is an infinite set of points generated by a set of discrete translation operations.
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 12
14 Bravais Lattices (3D)
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 14
Background image of page 15

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 16
Cubic Lattices Simple Cubic Body Centered Cubic Face Centered Cubic
Background image of page 17

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Diamond Crystal Structure
Background image of page 18
Diamond Crystal Structure
Background image of page 19

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Lattices vs. Crystal Structures There are 14 unique lattices – called Bravais Lattices – defined by symmetry considerations. Crystal structures are lattices that have an atom, molecule or group of atoms associated with each site of the lattice. For this class we are mostly interested in a subgroup of lattices called cubic lattices. Cubic lattices can be represented by a unit cell that is shaped like a cube although there may be more than just the corner sites as lattice points.
Background image of page 20
Semiconductor Crystal Structures Diamond structure – crystalline structure of Si, Ge, diamond It is a face centered cubic crystal with two atoms per site. It results from the covalent bonding of the atoms in a tetrahedral arrangement. The tetrahedron is the basic building block of these materials.
Background image of page 21

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 22
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/04/2010 for the course EE 338 taught by Professor Dapkus during the Spring '07 term at USC.

Page1 / 60

Class1_Slides - Physical Electronics EE.338 Steve Cronin...

This preview shows document pages 1 - 22. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online