In the last years many progresses have been made in the field of Silicon Single Photon Avalanche Diodes (SPAD) thanks to the improvements both in device design and in fabrication technology. For example, the use of custom fabrication processes has allowed a steadily improvement of SPAD performance in terms of active area diameter, Dark Count Rate (DCR), and Photon Detection Efficiency (PDE). Although a significant breakthrough has been achieved with the recent introduction of a new device structure capable of combining a good timing resolution with a remarkable PDE in the near infrared region, nevertheless there is still room for further improvements. In this paper we will discuss further modifications to the device structure enabling the fabrication of arrays with red enhanced photon detection efficiency.