How are semiconductor devices fabricated?

Semiconductor devices are fabricated through a series of complex processes involving lithography, deposition, and etching.

To begin the fabrication process, a thin layer of silicon dioxide is deposited onto a silicon wafer. Next, a layer of photoresist is applied to the surface of the silicon dioxide. The photoresist is then exposed to ultraviolet light through a mask, which defines the pattern for the device.

After the photoresist is developed, the exposed areas of the silicon dioxide are etched away using a chemical process. This leaves behind a patterned layer of silicon dioxide on the surface of the silicon wafer.

The next step is to deposit a layer of dopant material onto the silicon wafer. This is typically done using a process called ion implantation, which involves bombarding the wafer with ions of the desired dopant material.

Once the dopant layer has been deposited, the wafer is heated to a high temperature in a process called annealing. This causes the dopant atoms to diffuse into the silicon, creating the desired electrical properties.

Finally, a series of additional lithography, deposition, and etching steps are used to create the various layers and structures that make up the final semiconductor device. These steps are repeated multiple times to create complex devices with multiple layers and intricate geometries.