How flat are silicon wafers?

Silicon wafers are measured in microns. Ultra flat wafers are wafers that are under 200 microns thick. The thickness of the wafer determines what kind of integrated circuits are used and if the wafer is ideal for supporting cells.

What is wafer flat?

Wafer Flats: Primary Flat = The flat of longest length located in the circumference of the wafer. The primary flat has a specified crystal orientation relative to the wafer surface; major flat. Secondary Flat = Indicates the crystal orientation and doping of the wafer. The location of this flat varies.

What’s the difference between a 100 and a 111 silicon wafer?

The location of this flat varies. By observing the angle between primary & secondary flats we can distinguish silicon wafer <100> & <111> 1. 90° angle between flats indicates it is a p type <100> silicon wafer 2. 180° angle between flats indicates it is a n type <100> silicon wafer 3.

Where are the flats located on a silicon wafer?

There are two flats: 1. Primary Flat: The flat of longest length located in the circumference of the wafer. The primary flat has a specific crystal orientation relative to the wafer surface. 2. Secondary Flat: The flat of shortest length located in the circumference of the wafer.

Why are silicon wafers used in all orientations?

The use of contact bonding technology, such as the electrochemical bonding method, allows contact-bonded silicon and boron-gallium-silicon bonds to form on the surface of the wafer in the flat state. [Sources: 7] Therefore, primary flat silicon wafers are often used as a reference for all types of wafer orientations.

What kind of impurities are used in silicon wafers?

Silicon wafers that are doped with impurities such as Boron create P- type wafers and wafers that are doped with Arsenic or Phosphorous create N-type wafers. The P type wafers have several positive charged holes whereas N type wafers have several negative charged electrons in it.