Processing-Induced Electrically Active Defects in Black Silicon Nanowire Devices

Silicon nanowires (Si NWs) are widely investigated nowadays for implementation in advanced energy conversion and storage devices, as well as many other possible applications. Black silicon (BSi)-NWs are dry etched NWs that merge the advantages related to low-dimensionality with the special industrial appeal connected to deep reactive ion etching (RIE). In fact, RIE is a well established technique in microelectronics manufacturing. However, RIE processing could affect the electrical properties of BSi-NWs by introducing deep states into their forbidden gap. This work applies deep level transient spectroscopy (DLTS) to identify electrically active deep levels and the associated defects in dry etched Si NW arrays. Besides, the successful fitting of DLTS spectra of BSi-NWs-based Schottky barrier diodes is an experimental confirmation that the same theoretical framework of dynamic electronic behavior of deep levels applies in bulk as well as in low dimensional structures like NWs, when quantum confinement conditions do not occur. This has been validated for deep levels associated with simple pointlike defects as well as for deep levels associated with defects with richer structures, whose dynamic electronic behavior implies a more complex picture.

In questo articolo si presentano i risultati di uno studio su nano-fili di Silicio (Si NWs), strutture potenzialmente molto interessanti per applicazioni nello sviluppo di dispositivi per la conversione e lo stoccaggio energetico. In particolare, si analizzano le caratteristiche di Black Si NWs ottenuti per deep reactive ion etching del silicio utilizzando la tecnica DLTS.