Thin-film tunneling transistors on flexible plastic substrates based on stress-assisted lateral growth of polycrystalline germanium

Stress-assisted Cu-induced lateral growth of polycrystalline germanium (poly-Ge) at temperatures as low as 150 °C has been exploited to fabricate thin-film tunneling transistors on flexible plastic substrates. Applying external compressive stress during annealing, leads to the lateral growth of poly-Ge from Cu-seeded drain/source regions, progressing into the channel area. A potential barrier is formed midway in the channel where the two lateral growth frontiers, emanating from source and drain seeded areas, meet each other. As confirmed by electrical measurements, the barrier is controlled by the gate bias. An ON/OFF ratio of 104 has been measured for these transistors, which shows the potential of these devices for switching applications.