Chapter31_PN-Electrostatic

Chapter31_PN-Electrostatic - Chapter 3 – The PN Junction...

Info iconThis preview shows pages 1–8. 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

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: Chapter 3 – The PN Junction 3.1 PN-Junction Electrostatics 3.2 I-V Characteristic 3.3 Dynamic Behavior 3.4 Diode Circuit Models 3.5 Diode Applications and Circuits 3.6 SPICE Analysis Literature: Pierret, Chapter 5-7 Jaeger Blalock, Chapter 3 Slides courtesy of Prof. Oliver Brand 2 September 11, 2011 ECE 3040: Chapter 3.1 – PN Junction O. Brand, 2 of 20 The PN Junction I = I s e qV A /kT − 1 [ ] I-V Characteristic P N Circuit Symbol + Forward Bias – – Reverse Bias + 3 3.1 PN Junction: Electrostatics 3.1.1 PN Junction Basics – Junction Approximations – Band Structure – Built-In Potential 3.1.2 Step PN Junction – Equilibrium V A = 0 – External Bias V A ≠ 0 3.1.3 Linearly Graded PN Junction – Equilibrium V A = 0 – External Bias V A ≠ 0 Pierret, Chapter 5, page 195-226 4 3.1.1 PN Junction Basics • Example: Diffusion of acceptor atoms (e.g. boron) in n- substrate • Metallurgical junction at N A = N D or N D – N A =0 Net Doping N D – N A Pierret, Fig. 5.1 5 Doping Profile Approximations for PN Junctions Approximations for doping profile in pn junctions: • Step Junction : approximation for ion implantation or shallow diffusion into lightly doped wafer • Linearly Graded Junction : approximation for deep diffusion in moderately to heavy doped wafer Step Junction Linearly Graded Junction Pierret, Fig. 5.2 6 PN Junction Band Diagram • Equilibrium requires the Fermi level to be constant across the device • Regions far away from the metallurgical junction will be unaffected • Electrons diffuse from n- to p- side, holes from p- to n-side, leaving behind unbalanced dopant site charges • This space charge creates an electric field (band bending), resulting in a carrier drift balancing the carrier diffusion (J tot = 0) Pierret, Fig. 5.3 qV bi 7 PN Junction Band Diagram • Equilibrium requires the Fermi level to be constant across the device • Regions far away from the...
View Full Document

This note was uploaded on 10/12/2011 for the course ECE 3040 taught by Professor Hamblen during the Fall '07 term at Georgia Institute of Technology.

Page1 / 21

Chapter31_PN-Electrostatic - Chapter 3 – The PN Junction...

This preview shows document pages 1 - 8. Sign up to view the full document.

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