ZnO Gate Based MOSFETs for Sensor Applications

In recent years, studies on zinc oxide (ZnO) films have drawn considerable interest because of their good electrical and optical properties, in combination with their wide bandgap, abundance in nature, and absence of toxicity. Owing to its varied physical properties such as electro-optical, acousto-optical, piezoelectrical and luminescence characteristics make ZnO as one of the most obvious choices   for sensor applications [1].

Monitoring and control of the environment is very crucial part everywhere ranging from small scale laboratories to the most advanced industrial facilities. The interface that operates between the system and its surroundings and enables us to act accordingly is called as a sensor. Sensors are one of the most indispensable parts of today’s technology.

 For the investigation of this, we fabricate a MOSFET with ZnO as its gate metal. We use a four level mask to fabricate the MOSFET, the first level for making the diffusion wells for source and drain. The second level to form the via holes for Aluminum deposition followed by the third level to shape the source and drain contact structures. Finally the fourth level mask to deposit ZnO gate metal. The ZnO gate metal was deposited by sputtering process. The electrical characteristic analysis was performed on the fabricated MOSFETs. We investigate the usage of these MOSFETs for various sensor applications which include but not restricted to gas and UV sensor applications.

REFERENCES

[1] P.P.Sahay, Journal of Material Sciences 40 (2005) 4383-4385

[2] Yongki Min, “Properties and Sensor Performance of Zinc Oxide Thin Films”, Massachusetts Institute of Technology, September 2003

[3] Eujune Lee, Dong-Il Moon, Ji-Hwan Yang, Keong Su Lim, and Yang-Kyu Choi, “Transparent Zinc Oxide Gate Metal–Oxide–Semiconductor Field-Effect Transistor for High-Responsivity Photodetector” IEEE Electron Devices Letters, Vol 30, No.5, May 2009