Solid materials have 3 types crystal structures:

1. Crystalline – Regular geometric periodicity throughout the entire volume of material.
2. Polycrystalline – Partially periodic structure throughout the entire volume of material. Degree of order over many atomic or molecular dimensions.
3. Amorphous – Non-periodic geometric structure. Degree of order only within a few atomic or molecular dimensions.

Arrangement of atoms in solids is called arrangement of lattices.

Most semiconductors like silicon, germanium and compound semiconductors show crystal arrangement called cubic lattice.

Cubic class of crystal exhibit following structures:

1. Simple Cubic – Polonium (more radioactive material)
2. Body Centered Cubic – Tungsten, Molybdenum, Tantalum.
3. Face Centered Cubic – Copper, Gold, Silver, Platinum.
4. Zinc blend cubic – Silver and GaAs
5. Diamond – Silicon