Growth of microcrystalline silicon (μc-Si) thin films with different preferential orientations has been studied employing XRD measurements versus thickness. The focus of this study is on the influence of preferential orientation on the film growth process. The (220) preferential orientation and randomly oriented μc-Si films studied here were prepared by VHF-PECVD at 180 °C. The thickness evolution revealed that the crystallinity was improved in the μc-Si with (220) preferential orientation μc-Si particularly in the first 0.5-μm of growth, while that in the randomly oriented μc-Si was almost completely unchanged. The difference in the crystallinity in the initial growth region arises from a difference in the growth mechanisms. Specifically, the growth of μc-Si with (220) preferential orientation can be elucidated by a hybrid-phase mode consisting of vapor- and solid-phase growth, whereas the growth of randomly oriented μc-Si can be achieved only by vapor-phase growth as occurs conventionally. Based on the growth mechanisms, the microstructures of μc-Si with both orientations and their influence on the photovoltaic performance are discussed.