lecture16

lecture16 - 6.720J/3.43J - Integrated Microelectronic...

Info iconThis preview shows pages 1–6. 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

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 16-1 Lecture 16 - p-n Junction (cont.) March 12, 2007 Contents: 1. Non-ideal and second-order effects Reading assignment: del Alamo, Ch. 6, 6.4 Announcements: Quiz 1: March 13 , 7:30-9:30 PM; lectures #1-12 (up to SCR-type transport). Open book. Calculator required . 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 16-2 Key questions What happens if there is SCR generation and recombination in a pn diode? If the doping distribution in a p-n junction is non-uniform, is the basic operation of the diode changed in a fundamental way? What happens to the C-V characteristics, I-V characteristics, and the dynamics of a p-n diode with non-uniform doping dis- tributions? 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 16-3 1. Non-ideal and second-order effects Space-charge generation and recombination In real devices, non-ideal I V characteristics often seen: log |I| qV/kT e qV/2kT e I S V Anomalies often due to: recombination through traps in SCR (in forward bias) generation through traps in SCR (in reverse bias) 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 16-4 Simple model for SCR generation and recombination. Starting point: trap-assisted G/R rate equation: U tr = np n o p o ho ( n + n i ) + eo ( p + n i ) In SCR: qV 2 np = n i exp kT Then: n i (exp qV U tr SCR = 2 kT 1) | ho n + eo p + ( ho + eo ) n i SCR G/R current: x n J SCR = q U tr dx x p Since n and p changing quickly with x in SCR, no analytical solution. 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 16-5 Analytical model: 2 n i (exp qV kT 1) U tr | SCR = ho n + eo p + ( ho + eo ) n i Since np constant, point of SCR with highest U tr where: ho n = eo p At that point: n i qV U tr | SCR,max = 2 eo ho (exp 2 kT 1) Use this across entire SCR upper limit to current: qn i x SCR qV J SCR,max = 2 eo ho (exp 2 kT 1) Cite as: Jess del Alamo, course materials for 6.720J Integrated Microelectronic Devices, Spring 2007. Cite as: Jess del Alamo, course materials for 6....
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

lecture16 - 6.720J/3.43J - Integrated Microelectronic...

This preview shows document pages 1 - 6. Sign up to view the full document.

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