Solving Numericals from Previous Year Questions (PYQ) | GATE Electronic Devices - Part 23

TL;DR

This video explains how to calculate the approximate peak electric field at the junction of a highly doped diode.

Transcript

friends in this video we are going to discuss about a previous year gate question on electronics device as you loop into the question you can see that a diode has been given and the P region of the diode is highly doped where na is too much greater than NB that's why the width of the depletion layer in the p-type is very thin whereas the width of t... Read More

Key Insights

• 🙅 The P-region of the diode is highly doped, resulting in a thin depletion layer, while the N-region has a width of 0.2 micrometers.
• 😆 The peak electric field at the junction can be approximated using the equation Emax = (Q * Nd * xnR) / εs.
• 😀 In the calculation, the value of XP (width of the depletion layer in the P-side) can be neglected due to the large difference in doping concentrations.

Questions & Answers

Q: What is the significance of the highly doped P-region in the diode?

The highly doped P-region results in a thin depletion layer, which significantly affects the electric field distribution and contributes to the peak electric field at the junction.

Q: How is the peak electric field approximated in the calculation?

The peak electric field, denoted as Emax, is approximated using the equation Emax = (Q * Nd * xnR) / εs, where Nd is the doping concentration and xnR is the width of the depletion layer.

Q: Can the value of XP (width of the depletion layer in the P-side) be neglected in the equation?

Yes, since the doping concentration NA is much greater than the doping concentration Nd, XP is much smaller than XN. Therefore, XP can be neglected in the calculation of Emax.

Q: What is Q in the equation for Emax?

Q represents the charge and is equal to 1.6 x 10^-19 Coulombs, which is the elementary charge.

Summary & Key Takeaways

• The video discusses a previous year Gate question on an electronics device, specifically a highly doped diode with a thin depletion layer in the P-region and a width of 0.2 micrometers in the N-region.

• It explains that the peak electric field occurs at the junction point and can be approximated using the equation Emax = (Q * Nd * xnR) / εs, where Q is the charge, Nd is the doping concentration, xnR is the width of the depletion layer, and εs is the permittivity.

• Using the given values, the video calculates the approximate peak electric field at the junction to be 30.65 kilovolts per centimeter.