NATIONAL UNIVERSITY OF MODERN LANGUAGES
Submitted to: Sir Rizwan
Submitted by: Zain Ali
Roll no: 9244327
Subject: Physics
Semester: 1st
Date: 28/11/2024
Assignment # 02
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, Applied Physics Assignment 2
Question: How a Diode is fabricated at industrial level. Write the complete process in detail. Draw proper diagrams and
label them. Use proper referencing style. Handmade assignments will not be accepted.
The Industrial Fabrication of Diodes:
The fabrication of diodes consists of a series of detailed steps that convert raw silicon into a fully operational diode. A diode
serves as a semiconductor device that permits the flow of current in a unidirectional manner. The predominant type of diode
utilized is the p-n junction diode, which is constructed from silicon. The following section presents a streamlined outline of
the manufacturing process of diodes in industrial settings.
1). Preparation of Silicon Wafers
First, we get the main ingredient, silicon, and clean it up.
• Cleaning: We take silicon from sand (which is silicon dioxide) and heat it in a furnace to purify it.
• Making Crystals: The cleaned silicon is melted, and a small piece of silicon is gently pulled out to create a big round block
called an "ingot." This block is then cut into thin, flat discs called wafers. We polish these wafers to make them smooth and
shiny, which is important for what comes next.
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| Silicon Ingot | <--- Made using the Czochralski method
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| | <--- This is the silicon wafer post-slicing
| Silicon Wafer |
2). Formation of P-N Junction
Doping involves adding small amounts of different materials to a silicon wafer to change how it conducts electricity. This
wafer is split into two areas: one is p-type, and the other is n-type.
- For the p-type area, boron is introduced, creating "holes" where electrons can fit in, which gives this section a positive
charge.
- On the other hand, to form the n-type area, phosphorus is added, which brings in extra electrons, resulting in a
negative charge.
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