Breakdown Enhancement in Silicon Nanowire p-n Junctions

Abstract

We demonstrate highly reproducible silicon nanowire diodes fabricated with a fully VLSI compatible etching technology, with diameters down to 30 nm. A contact technology based on recrystallized polysilicon enables specific contact resistances as low as rho approximately 10-7 Omega cm2. Our devices show a strongly diameter-dependent breakdown voltage at reverse bias, which we explain in terms of the influence of the surrounding dielectric. We suggest that this technology is suitable for incorporating nanowire-based functionalities into future integrated circuits.

Visualization of Carrier Depletion in Semiconducting Nanowires

“…It has long been known that nearby dielectrics (and field‐shaping electrodes) can enhance the breakdown voltage in planar junctions via a reduction of the maximum surface field 3. Similarly, the electric field inside SiO 2 ‐embedded NW pn junctions is smeared out and charge carriers experience a potential landscape controlled by the dielectric environment, which in turn results in even a suppression of avalanche breakdown 4. Thus, a technique to directly map the space–charge layer in NWs would be of general interest.…”

Current Rectification in a Single Silicon Nanowire p–n Junction

“…On the other hand, homojunctions to NW diodes can minimize this contact contribution. 12 When a reverse bias is applied, a small current can flow due to one of two possible breakdown mechanisms, avalanche or tunneling (or Zener). 13 An avalanche breakdown is more abrupt and occurs at about 5-6 V. In case of tunneling, as the reverse bias is increased, the energy band-bending will further reduce the energy barrier width, increasing the tunneling probability.…”

Characterizing the Two-Dimensional Doping Concentration inside Silicon-Nanowires Using Scanning Spreading Resistance Microscopy

“…For nanowires with incorporated p-n junctions, a thin metal layer of 5 nm TiW is deposited on top of the nanowire sample before the cleaving step. They are fabricated by a procedure as described elsewhere [10]. Figure 3.…”