Unraveling Structure and Device Operation of Organic Permeable Base Transistors

Organic permeable base transistors (OPBTs) are of great interest for flexible electronic circuits, as they offer very large on‐current density and a record‐high transition frequency. They rely on a vertical device architecture with current transport through native pinholes in a central base electrode. This study investigates the impact of pinhole density and pinhole diameter on the DC device performance in OPBTs based on experimental data and TCAD simulation results. A pinhole density of NPin = 54 µm−2 and pinhole diameters around LPin = 15 nm are found in the devices. Simulations show that a variation of pinhole diameter and density around these numbers has only a minor impact on the DC device characteristics. A variation of the pinhole diameter and density by up to 100% lead to a deviation of less than 4% in threshold voltage, on/off current ratio, and sub‐threshold slope. Hence, the fabrication of OPBTs with reliable device characteristics is possible regardless of statistical deviations in thin film formation.