Structure of Germanium and Silicon
Structure of germanium and Silicon
One of the 104 known chemical materials that cannot be subdivided into simpler substances is called as element. The smaller portion of an element that still exhibits all the characteristics of that element is called an atom. You know that metals such as copper and aluminum are used to carry current in an electrical circuit. Metals which carry current are classified as conductors because they offer minimum opposition to, current flow. Materials such as glass, rubber and ceramic oppose the flows of electric current and are therefore classified as insulators.
Let us understand the atomic structure of two materials Germanium and Silicon, the most widely used semiconductors.Before we actually examine the structure of Germanium and Silicon atoms, it would be wise to understand the Structure of Atom.
The two semiconductor materials most commonly used in the construction of transistor and other types of related components are germanium and silicon. Both Germanium and Silicon materials are made up of atoms which have 4 electrons in their furthest or valence shells.
A single Germanium atom has 4 shells and the distribution of the electrons from the first shell to the outer shell is 2, 8, 18 and 4. Henceforth, a total of 32 electrons swivel in the region of the nucleus of the atom and a total of 32 protons are enclosed within the nucleus.
A single Silicon atom has 3 shells and the distribution of the electrons from the first shell to the outer shell is 2, 8 and 4.The atom has a sum of 14 electrons rotating around its nucleus and a totality of 14 protons in its nucleus.
Each atom shares its 4 valence electrons with 4 neighboring atoms. The sharing of electrons creates a bond which holds the atoms together. This electrons pair bond is commonly referred to as a covalent bond and it occurs because each of the atoms in the structure tries to take on additional electrons in order to fill its valence shell with 8 electrons.
Si atoms combine in the same manner as Ge atoms to form the same type of crystalline structure.
The germanium and silicon crystal lattices just described are free from impurities and therefore represent pure or idea material. Such crystals are frequently termed to as intrinsic materials. The construction of solid state components such as transistor depends on the use of these pure or intrinsic semiconductor materials.