page_title: Sheet resistance
section_title: Calculations
hierarchical_section_title: Sheet resistance / Calculations
context_page_description: Sheet resistance, often called sheet resistivity, is a measure of resistance of thin films that are nominally uniform in thickness. It is commonly used to characterize materials made by semiconductor doping, metal deposition, resistive paste printing, and glass coating. Examples of these processes are: doped semiconductor regions, and the resistors that are screen printed onto the substrates of thick-film hybrid microcircuits.
  The utility of sheet resistance as opposed to resistance or resistivity is that it is directly measured using a four-terminal sensing measurement or indirectly by using a non-contact eddy-current-based testing device. Sheet resistance is invariable under scaling of the film contact and therefore can be used to compare the electrical properties of devices that are significantly different in size.
context_section_description: Sheet resistance is applicable to two-dimensional systems in which  thin films are considered two-dimensional entities. When the term sheet resistance is used, it is implied that the current is along the plane of the sheet, not perpendicular to it.
  In a regular three-dimensional conductor, the resistance can be written as
  where  is the resistivity,  is the cross-sectional area, and  is the length.  The cross-sectional area can be split into the width  and the sheet thickness .
  Upon combining the resistivity with the thickness, the resistance can then be written as
  where  is the sheet resistance. If the film thickness is known, the bulk resistivity  (in Ω·cm) can be calculated by multiplying the sheet resistance by the film thickness in cm:
caption: Geometry for defining resistivity (left) and sheet resistance (right). In both cases, the current is parallel to the  L direction.