White electroluminescent nanostructures in silicon fabricated using focused ion implantation

The use of an accelerator fed microbeam as an implanter enables highest fle xibility in doping substrates. Dopant, implantation dose, and pattern can b e chosen individually and adopted to sequentially implanted structures. On the other hand, high throughput of arbitrarily shaped and identically doped samples, as needed in semiconductor device fabrication, can be achieved in conjunction with the Bochum Ion Projector. This machine is capable of focu sing an ion beam down to 300 run and allows both, prototyping and small ser ies production of devices without the need of a coating mask on the substra te surface. We report on a method for producing nanoscale white light emitt ing structures by focused ion beam implantation in crystalline silicon. Foc used ion beam implantation of acceptor ions into n-type doped Si yields lat eral npn-junctions. These junctions emit light from their nanoscale depleti on zones if operated in (reverse biased) breakdown mode, depending on volta ge polarity on either side of the implanted area. The actual ion beam diame ter is not a limiting factor for the submicron width light sources because radiation originates only from depletion zones with lateral sizes in the or der of 100 mn. Compatibility with standard silicon processing allows monoli thic integration of such light sources in conventional circuit designs. The ir emission spectrum covers the whole visible range without showing sharp p eaks. However, three distinct maxima can be observed. Their positions and r elative heights slightly vary with implantation dose and applied voltage. ( C) 2001 Elsevier Science B.V. All rights reserved.