Transcript JAVA Applets-For Physical Electronics

JAVA Applets for Physical
Electronics.
Metal
Semiconductor
Metal
Semiconductor
Depletion Region
Team Members
Team Leader/Presentation
Ramya Chandrasekaran
Webmaster/Documentation
Pujita Pinnamaneni
Project Goal
• Design a JAVA Applet to help students understand
the characteristics of Schottky diodes.
• Demonstrate the energy band gap and depletion
width variations for varying concentrations and for
different metals and semiconductors.
• Demonstrate how the free carrier concentration
varies with temperature.
Project Outline
• Review semiconductor physics of Schottky
diodes.
• Develop simulation for band gap variation
with respect to concentration for different
metals and semiconductors.
• Develop simulation of n/ND and p/NA
vs.temperature.
Project Outline(cont.)
• Develop JAVA code to run these
simulations.
• Design JAVA applets.
• Demonstrate the applets.
• Launch the Applets on the World Wide
Web.
Importance of JAVA Applets
• JAVA enables to develop user friendly
applications.
• JAVA is the web language.
• Enables easy interaction .
• GUI concepts in JAVA accepts user inputs through
mouse and keyboard and enables immediate
feedback.
• Animations and interactive applications are
possible.
Importance of Schottky diodes
• The role of schottky diodes is firmly established in
the semiconductor technology because they
perform functions better than most of the other
junction devices.
• These contacts are used in large number of devices
such as FETs,BJTs,photo detectors,LEDs,Double
Heterostructure lasers and Solar cells.
• Metal - Semiconductor junction are used for high
speed rectification.
Simulation of Schottky diodes.
Schottky diodes are formed in two ways:
• Metals deposited on n-type semiconductor.
• Metals deposited on p-type semiconductor.
Schottky Contacts.
In n-type Schottky contacts,electrons flow
from the conduction band states in the
semiconductor to the metal because they
have higher energy states.
In p-type Schottky contacts,electrons flow
from the metal to semiconductor.
Metal on n-type Semiconductor
Metal on p-type Semiconductor.
Temperature Vs Free carrier
Concentration
The regions on the curve are:
• Freeze-out:
Depicts the unionized dopants
• Extrinsic Region:
Represents ionized dopants and control
conductivity.
• Intrinsic Region:
Characterizes broken covalent bonds
Basic Principles(cont…)
Physics Involved
The intrinsic carrier concentration is calculated
ni = nio * (T/To)1.5 * exp [(Eg / 2KTo) * (1- To/T)
ND1= [( Nd1/ (1+2[Nd1/(NCO * ni1.5)] ) exp (( Ec – Ed1)/KT)]
Conclusions
• Simulation of Schottky diodes using JAVA
Applets is accomplished.
• Temperature Vs. Free carrier concentration
curves for different semiconductors have
been plotted.
• Applets have been successfully hosted on
the World wide web.