Concept for two-dimensional TMDs as functional layer for gas sensing applications

This work presents a concept, which combines the benefits of 2D materials such as MoS2 or WS2 with an 8-inch wafer scale integrated circuit fabrication for gas sensing applications. The results of first tests with different substrates such as silicon, glass and polymers are presented herein. Surface properties in terms of roughness as well as compatibility to common Al2O3 ALD processes are investigated. Here, the option of covering not only silicon, but also polymers with Al2O3 at 300 °C is demonstrated. With these fundamental results, there is no obstacle to the future development of an ALD process with a new precursor chemistry. Moreover, a CMOS-compatible post-processing of the TMD WS2 is studied. For this purpose, Raman spectra of an uncovered and a WS2 layer encapsulated in Al2O3 were collected and compared. It shows in addition to an entire reduction of the Raman signal, that particularly the out-of-plane vibration decreases.