Sensing device, sensing apparatus and sensing system
A sensing device includes a first III-V compound stack and a second III-V compound stack. The first III-V compound stack has a first sensing area, and the second III-V compound stack has a second sensing area. A passivation layer fully covers the second sensing area. The first III-V compound stack is physically separated from the second III-V compound stack, and has material compositions and structures same as the second III-V compound stack.
1. A sensing device, comprising:
a substrate made of an insulating material;
a first III-V compound stack in direct contact with the substrate and comprising a first semiconductor layer, and a second semiconductor layer formed on the first semiconductor layer; and
a second III-V compound stack in direct contact with the substrate, and comprising a third semiconductor layer, a fourth semiconductor layer formed on the third semiconductor layer,
wherein the first III-V compound stack is separated from the second III-V compound stack by a trench, the trench has a lowest end which is higher than bottom surfaces of the first semiconductor layer and the third semiconductor layer.
2. The sensing device according to claim 1 , wherein the trench has a depth which is measured from a top surface of the second semiconductor layer to the lowest end and has a range from 35 nm to 235 nm.
3. The sensing device according to claim 2 , wherein the first III-V compound stack has a thickness, and the depth is less than the thickness.
4. The sensing device according to claim 1 , further comprising a sub-mount, wherein the first III-V compound stack and the second III-V compound stack are disposed on the sub-mount.
5. The sensing device according to claim 1 , wherein the first semiconductor layer has a portion connected to the third semiconductor layer.
6. The sensing device according to claim 1 , wherein the second semiconductor layer is fully separated from the fourth semiconductor layer.