Methods for controlling the grain structure of a polycrystalline Si-containing film involve depositing the film in stages so that the morphology of a first film layer deposited in an initial stage favorably influences the morphology of a second film layer deposited in a later stage. In an illustrated embodiment, the initial stage includes an anneal step. In another embodiment, the later stage involves depositing the second layer under different deposition conditions than for the first layer.
Trisilane is used in chemical vapor deposition methods to deposit silicon-containing films over mixed substrates. Such methods are useful in semiconductor manufacturing to provide a variety of advantages, including uniform deposition over heterogeneous surfaces, high deposition rates, and higher manufacturing productivity. An example is in forming the base region of a heterojunction bipolar transistor, including simultaneous deposition over both single crystal semiconductor surfaces and amorphous insulating regions.
