Semiconductor device having at least two thin film transistors

摘要

Two kinds of TFTs are fabricated by the same process with a high production yield to manufacture an active-matrix circuit and a peripheral driver circuit on the same substrate. The active-matrix circuit is required to have a high mobility and a high ON/OFF current ratio. The peripheral driver circuit needs a complex interconnection structure. The active-matrix circuit and the peripheral driver circuit comprising the TFTs are fabricated monolithically. In this step, the gate electrodes of the TFTs of the active-matrix circuit is coated with an anodic oxide on their top and side surfaces. The gate electrodes of the TFTs of the peripheral driver circuit is coated with the anodic oxide on only their top surfaces; substantially no anodic oxide is present on the side surfaces.