A
biochip for use in detecting
biological materials is provided. The
semiconductor device includes a substrate (110),
semiconductor layers (120, 121, 122, 123), an insulating layer (130), IL1, IL2,
metal layers (140, 141, 142, 143), a solution (200, 210, 220), a first protective layer (150, 152, 153) and a second protective layer (160, 161, 162, 163). The
semiconductor layer is disposed on the substrate and has a reaction region. The insulating layer is disposed on the semiconductor layer and has a first opening (O1) exposing the reaction region. The
metal layer is disposed on the insulating layer (130). The
metal layer includes a source
electrode (141), a drain
electrode (142) and a surrounding wall structure (143). The source
electrode and the drain electrode are electrically connected to the semiconductor layer, respectively. The surrounding wall structure has a first opening (O1). The opening surrounds the source electrode and the drain electrode. A first protective layer is disposed on the metal layer and has a second opening O2. A second protective layer is disposed on the first protective layer and has a third opening O3 and a fourth opening O4. The second protective layer includes a first protrusion 161, a second protrusion 162 and a third protrusion 163. The first protrusion is disposed corresponding to the source electrode, the second protrusion is disposed corresponding to the drain electrode, and the third protrusion is disposed corresponding to the surrounding wall structure, surrounding and defining the fourth opening. A solution containing bioprobes 210 is disposed in the opening. In the normal direction of the substrate, the third opening overlaps the second opening and the first opening, and the fourth opening exposes the first protective layer.