Semiconductor Crystal Growth
Semiconductor crystal growth is the formation of single crystals or polycrystalline structures for use in semiconductor devices. Crystalline structures are created artificially, often through very precise manufacturing processes. It is an essential step in producing a range of semiconductor products, such as transistors, diode lasers, solar cells, and LEDs.
The process of semiconductor crystal growth can be divided into three main steps: preparation of a seed crystal, formation of a melt and growth of a larger crystal. The main difference between a typical crystal growth process and a semiconductor growth process is the special attention paid to the size, shape, and orientation of the formed crystal.
In the preparation of a seed crystal, a small piece of semiconductor material is cut from a larger piece and heated until it is completely melted. The molten crystal is then slowly cooled and allowed to solidify into a single crystal. Once the seed crystal has been created, it is ready for use in a semiconductor crystal growth process.
During the formation of a melt, the seed crystal is placed into a container of molten semiconductor material which is heated to a precise temperature that is a few degrees higher than the melting point of the material. The molten mass is then kept at this temperature, allowing it to remain as a single body. The seed crystal is then submerged in the molten material and kept floating on the surface.
Once the seed crystal is submerged in the melt, the third step of semiconductor crystal growth can be started. Generally speaking, this step involves pulling a small portion of the melt up onto the seed crystal which is heated until it melts and begins to form a larger crystal. This process is called the floating zone technique and is the most common method used for semiconductor crystal growth. Through careful control of the temperature during this process, the size, shape, and orientation of the crystal can be precisely controlled.
Once the crystal has grown to the desired size and shape, it is cooled and then cut or sliced into smaller pieces for use in semiconductor devices. This process is known as dicing and is necessary to ensure that the semiconductor device has the required electrical properties.
Semiconductor crystal growth is a complex and demanding manufacturing process that must be done with very precise control. The quality of the products produced will be directly affected by how well this process is managed and controlled. By paying close attention to the parameters involved, a manufacturer can ensure that the highest quality and most reliable devices are produced.
