Surface effect as a limitation on the performance of polycrystalline Si thin-film transistors

In a previous article [J. Appl. Phys. 62, 1503 (1987)], we demonstrated how the average grain size and the {110} fiber texture of a polycrystalline Si film could affect the performance of metal-oxide-semiconductor thin-film transistors fabricated in the film. We showed that, for grain sizes of the order of 1–2 μm, a strong {110} texture was more effective than a larger average grain size in improving the threshold voltages and field-effect carrier mobilities of both the n- and p-channel transistors fabricated. In this article, we propose an interpretation of these results, and offer supporting evidences, to relate the crystallographic texture of a polycrystalline Si film to thin-film transistor performance. We show that a {110}-oriented surface exhibits less surface effect than a randomly oriented surface on average and, consequently, it is more desirable for thin-film transistor applications.