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Polycrystalline silicon (polysilicon) has found many applications in integrated
circuits. Depending on the doping concentration it is used as conductor (gate in
metal oxide semiconductor field effect transistors (MOSFET) [20]) or
as a resistor (high value resistor in memory cells [3]). Polysilicon is
deposited on the wafer by low pressure chemical vapor deposition (LPCVD)
making use of the decomposition of silane (SiH
). It consists of small
crystallites called grains separated by thin regions called grain
boundaries. The grain size increases with an increase in the deposition
temperature [48] and it depends on the in-situ (dopants are added
during the deposition process) doping concentration. The average grain size
ranges from 0.3 
m to 1.0 m while the grain boundaries (interface
between two grains with different crystal orientation) are only 0.5 nm
to 1 nm wide.
Previous: 2.3.1 Crystalline Silicon
Up: 2.3 Target Materials Properties
Next: 2.3.3 Silicon Dioxide