Study of piezo-tunnel effect in Metal/A2O3/metal junctions

In this work, the electrical transport in Al/A
₂
O
₃
/Pt and Al/A
₂
O
₃
/Al junctions under mechanical stress was investigated. The junctions were fabricated by evaporation for the metals (with shadow mask lithography) and Atomic Layer Deposition (ALD) for the A
₂
O
₃
. First, IV characteristics were extracted from the unstressed sample and these curves were fitted with the Fowler-Nordheim current expression to identify the conduction mechanism. Then, gauges were tested under mechanical strain using the beam deflection method. Gauge factors of -34 for Al/A
₂
O
₃
/Al and -70 for Al/A
₂
O
₃
/Pt junctions were measured. Finally, the geometrical gauge factor is discussed and a possible effect of the variation of the Metal/A
₂
O
₃
interface's barrier height under stress is suggested as a plausible cause for the difference in gauge factor observed between the two junction types.