Lecture17(1)

# Lecture17(1)

This preview shows page 1. Sign up to view the full content.

This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: D xp o NA 2K S q o ND Vbi NA NA ND NA ND Vbi NAND One-Side Junction ECE 3080 - Dr. Alan Doolittle EE 332 Spring 2013 Qualitative band diagrams with applied voltage: Biased P-N Junction EE 332 Spring 2013 Carrier Flow in Biased Junction Current Flow - Qualitative Zero Bias diffusion drift diffusion Reverse Bias drift Forward Bias VA>0 EE 332 Spring 2013 EE 332 Semiconductor Materials and Devices Lecture 17. Carrier Injection in P-N Junction Diode 1.  2.  3.  Minority carrier injection Diode current I-V characteristics V Bias on P-N Junction Voltageoltage Bias on P-N Junction EE 332 Spring 2013 P-N Junction •  P-n Junction I-V Characteristics I-VPutting it all together Characteristics Putting it all together Forward Bias: Current flow is proportional to e(Va/Vref) due to the exponential decay of carriers into the majority carrier bands Reverse Bias: Current flow is constant due to thermally generated carriers swept out by E-fields in the depletion region Current flow is zero at no applied voltage I=Io(eVa/Vref - 1) Georgia Tech EECE 3080 - Dr. Alan Doolittle E 332 Spring 2013 Assumptions: Quantitative p-n Diode Solution 1) steady state conditions Current Quantitative Diode 2) non- degenerate doping 3) one- dimensional analysis Assumptions: Quasi-Neutral Regions 4) low- level injection 1) steady state conditions 5) no light (GL = 0) 2) non- degenerate doping 3) one- dimensional analysis Current equations: p-type n-type Quasi-Neutral Regions 4) low- level injection J=Jp x (GL 5) no light Jn(x)= 0) Jn =q nnE +qD Current equations:n(dn/dx) J=Jp x Jn(x) Jp = q ppE - qDp (dp/dx) Jn =q Georgia Tech Jp = q nnE +qDn(dn/dx) ppE - qDp (dp/dx) Depletion Region p-type n-type VA Depletion Region VA ECE 3080 - Dr. Alan Doolittle EE 332 Spring 2013 eorgia Tech ECE 3080 - Dr. Alan Doolittle EEqualibrium Carrier Concentrations quilibrium Carrier Concentrations EE 332 Spring 2013 N p the e in depletion t tp 2 tn 2 n x e2xist exist inLexistxistthethe depletion x in nthe depletion in depletion 2 2 ( (nD)p ) ( ( n n) )2 ( ( n p )(region, region, the minoritypn ) ( 0pn )D ( p( 2 pn ) pn pp the region, the minority 2 n P0 n )(2 pn minority DP 0 ( DP np ) n) region, pthe minority 0 N 0 2 2 2 0 DP x 2 0 DN x xp xn p n x x2 n carrier carrier diffusion x diffusion x Minority Carrier Injection carrier diffusioncarrier diffusion n Application of the minority quationdiffusion equation Quantitativedoes carrier SolutionSolution e does not eQuantitative p-n Diode Solution quation Diode Diode equation p-n...
View Full Document

## This document was uploaded on 02/18/2014.

Ask a homework question - tutors are online