lecture7 - 6.720J/3.43J- Integrated Microelectronic...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon

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

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

Unformatted text preview: 6.720J/3.43J- Integrated Microelectronic Devices- Spring 2007 Lecture 7-1 Lecture 7- Carrier Drift and Diffusion (cont.) February 20, 2007 Contents: 1. Non-uniformly doped semiconductor in thermal equi- librium Reading assignment: del Alamo, Ch. 4, 4.5 Cite as: Jess del Alamo, course materials for 6.720J Integrated Microelectronic Devices, Spring 2007. MIT OpenCourseWare (http://ocw.mit.edu/), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY]. 6.720J/3.43J- Integrated Microelectronic Devices- Spring 2007 Lecture 7-2 Key questions Is it possible to have an electric field in a semiconductor in ther- mal equilibrium? What would that imply for the electron and hole currents? Is there a relationship between mobility and diffusion coecient? Given a certain non-uniform doping distribution, how does one compute the equilibrium carrier concentrations? Under what conditions does the equilibrium majority carrier con- centration follow the doping level in a non-uniformly doped semi- conductor? Cite as: Jess del Alamo, course materials for 6.720J Integrated Microelectronic Devices, Spring 2007. MIT OpenCourseWare (http://ocw.mit.edu/), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY]. 6.720J/3.43J- Integrated Microelectronic Devices- Spring 2007 Lecture 7-3 1. Non-uniformly doped semiconductor in thermal equilibrium It is possible to have an electric field in a semiconductor in thermal equilibrium non-uniform doping distribution Gauss Law: electrical charge produces an electric field: d E = dx volume charge density [ C/cm 3 ] if = 0 d E = 0 dx in a certain region, it is possible to have E = 0 with = 0 if there are charges outside the region of interest In semiconductors: = q ( p n + N D + N A ) If N D + N D and N A N A , d E q = ( p n + N D N A ) dx Cite as: Jess del Alamo, course materials for 6.720J Integrated Microelectronic Devices, Spring 2007. MIT OpenCourseWare (http://ocw.mit.edu/), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY]. 6.720J/3.43J- Integrated Microelectronic Devices- Spring 2007 Lecture 7-4 d E q = ( p n + N D N A ) dx Uniformly-doped semiconductor in TE: far away from any surface charge neutrality : o = 0 d E o = 0 dx since no field applied from the outside E o = 0 Cite as: Jess del Alamo, course materials for 6.720J Integrated Microelectronic Devices, Spring 2007....
View Full Document

This note was uploaded on 09/24/2010 for the course EECS 6.720J taught by Professor Jesúsdelalamo during the Spring '07 term at MIT.

Page1 / 17

lecture7 - 6.720J/3.43J- Integrated Microelectronic...

This preview shows document pages 1 - 5. Sign up to view the full document.

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