Performance Improvement in Vertical Surface Tunneling Transistors by a Boron Surface Phase

The fabrication and characteristics of silicon tunneling transistors based on vertical metal-oxide-semiconductor (MOS) gated pin-diodes are shown. In these devices the tunnel junction is formed between an influenced MOS-channel and an abrupt, ultra-highly doped boron layer. The ultra-high doping amount of about 2.6×1014 cm-2 is achieved by the formation of a √3×√3-R30° boron surface phase. The tunneling transport and the influence of the boron surface phase on the transistor behavior is investigated. The transistor performance is characterized by a current gain between 3 and 5 orders of magnitude at a low supply voltage of -0.2 V with saturation behavior.