Chapter 3   : Fabrication of CMOS Integrated Circuits


By measuring the sign of the thermo voltage between a hot tip (a soldering iron) and a room-temperature tip pressed on the wafer can indicate whether the wafer is n- or p-type.

The breaking (cleaving) of wafer indicate the orientation of a wafer; e.g. {100} wafer pieces will be rectangular.

In this section we have studied about different types of cubic crystal structures, packing densities, various crystal planes and directions, miller indices etc. In the next section we will study how the crystals are made.

3.1.2 Crystal Growth

Integrated circuits are built on single-crystal silicon substrates that possess a high degree of chemical purity, a high degree of crystalline perfection, and high structure uniformity. Such silicon crystal preparation involves two major steps: (1) refinement of raw material (such as quartzite, a type of sand) into electronic grade polycrystalline silicon (EGS) and (2) growing of single-crystal silicon from this EGS either by Czochralski or Float Zone process.