The dopants are introduced in the active areas of silicon by using which process ?

Explanation:

Ion Implantation in Silicon

Definition: Ion implantation is a process used to introduce dopants into the active areas of silicon in semiconductor device fabrication. This method involves accelerating ions of a dopant element to high energies and then directing them into the silicon wafer. The ions penetrate the silicon lattice and become embedded at specific depths, altering the electrical properties of the silicon.

Working Principle: During ion implantation, dopant ions are generated in an ion source and then accelerated by an electric field to a high velocity. These high-energy ions are directed towards the silicon wafer, where they penetrate the surface and come to rest at a certain depth, depending on their energy. The distribution and concentration of the implanted ions can be precisely controlled by adjusting the energy and dose of the ion beam.

Advantages:

• High precision in controlling the depth and concentration of dopants, allowing for the creation of well-defined junctions and regions within the silicon.
• Flexibility in doping different areas of the wafer with various dopants without the need for masking and patterning steps.
• Ability to create very shallow junctions, which is essential for modern, high-performance semiconductor devices.

Disadvantages:

• High equipment cost and complexity, requiring sophisticated machinery and vacuum systems.
• Potential damage to the silicon lattice due to the high-energy ion bombardment, which may necessitate subsequent annealing steps to repair the crystal structure.
• Limited throughput compared to other doping techniques, making it less suitable for high-volume manufacturing.

Applications: Ion implantation is widely used in the fabrication of integrated circuits, including the formation of source and drain regions in MOSFETs, the creation of buried layers in bipolar transistors, and the adjustment of threshold voltages in various devices.

Correct Option Analysis:

The correct option is:

Option 2: Ion Implantation

This option correctly identifies the process used to introduce dopants into the active areas of silicon. Ion implantation is a highly controlled and precise method that allows for the introduction of specific dopant concentrations at desired depths within the silicon wafer