TABLE OF CONTENTS Silicon with nanoscale crystalline grains ranging in size from a few nanometers to 1000 nm is referred to as nanocrystalline silicon (nano Si, n-Si). This form of silicon is usually composed of deposited layers of approximately 1 ?m thickness each. On the contrary, when exceeding 1000 nm in grain size, we enter the domain of microcrystalline silicon. In this paragraph, production and analysis of nanocrystalline silicon are discussed, essentially based on [121]. It can be manufactured using different deposition methods such as
Electron cyclotron resonance CVD (ECRCVD) [122],
Photo CVD [123],
Magnetron plasma CVD [124],
Plasma-enhanced CVD (PECVD) [125], [126],
Remote plasma-enhanced CVD [127],
Hydrogen radical CVD [128],
Spontaneous CVD [129], and
Reactive sputtering [130], [131].
In the following, emphasis is put on the PECVD procedure (cf. Sect. 5.4), which is done very similarly to the deposition of amorphous silicon. As a major difference, however, higher frequencies (e.g., 110 MHz) are preferred during nanocrystalline deposition instead of the usual 13.56 MHz. While being helpful for the production of films, this measure causes a problem regarding homogeneity: with 13.56 MHz the wavelength is 22 m, and it shortens to 2.7 m with 110 MHz. Thus, it lies within the limits of the chamber size and standing waves can develop. Consequently, precautions must be taken for large-surface deposition with frequencies above 60 MHz. For instance, by a multi-point feed of the HF power with...
