ABSTRACT
Silane (SiH4) has been extensively used in the microelectronics industry in essentially the same process with LCVD. In LCVD dealing with relatively larger substrates, however, derivatives of silane are preferentially used because derivatives are more stable and easy to handle. SiH4 reacts with oxygen in an explosive manner and requires special precautions in handling of the gas. The specific reactivity of Si with
oxygen makes the major difference from C-based compounds described above. O atoms in the structure of monomers act as retarder or inhibitor for plasma polymerization of C-based compounds, and compounds having O in their structure are reluctant to polymerize. In contrast to O in C-based compounds, O in siloxanes is stable and does not detach from Si, and the O/Si ratio remains nearly constant in plasma polymers of siloxanes whereas C/Si changes depending on the conditions of glow discharge. Furthermore, O2 acts as a comonomer in LCVD of silane and siloxane derivatives, and changes the characteristics of plasma polymers to the characteristics of inorganic or ceramic-type materials gradually according to the mole ratio of O2 added to the mixture.
