Evidence of a Novel Source of Random Telegraph Signal in CMOS Image Sensors

Radiation-Induced Variable Retention Time in Dynamic Random Access Memories

“…It suggests that the storage PN junction of the 2 GB cell has a larger sensitive depletion volume or more intense electric fields than its 4 GB counterpart. Overall, the fact that TID generates VRT cells is in very good agreement with the behavior of DC-RTS centers in image sensors where it has been clearly demonstrated that ionizing radiation generates a large number of metastable generation centers at the various CMOS Si/SiO2 interfaces [16], [20].…”

“…The purpose of this work is to demonstrate that displacement damage as well as ionizing radiation lead to the generation of VRT DRAM cells and that the responsible meta-stable generation centers can exist both at the Si/SiO 2 interface and in the silicon bulk. The cause of this original TID effect on DRAMs is most likely the same phenomenon as the TID induced DC-RTS observed in CMOS image sensors (CIS) [16]. This additional similarity to DC-RTS in solid-state image sensors [15], [17] strongly suggests that VRT, VJL, ISB and DC-RTS are in fact the exact same phenomenon and that there are many more possible defects than the V 2 O x complex or bulk defect clusters to explain the existence of this exotic mechanism.…”

“…Regarding the location of those DC-RTS centers, it has been clearly established that they can originate from any Si/SiO 2 interfaces (gate oxide, pre-metal-dielectric interface, gate oxide...) in unirradiated sensors [42] and that bulk DC-RTS centers are nonexistent (or extremely rare) in unirradiated sensors [43]. In CIS exposed to TID, all Si/SiO 2 interfaces surrounding the photodiode have been identified as possible source of DC-RTS centers [16], [29]. Finally, after a displacement damage irradiation, it is well known that DC-RTS is caused by bulk defects in CCDs [15] as well as in CISs [17] and in any kind of silicon device.…”

Investigation of Dark Current Random Telegraph Signal in Pinned PhotoDiode CMOS Image Sensors

“…Meta-stable interface states acting as SRH R-G centers in the TG channel, in the vicinity of the PPD, appeared to be responsible. The observed characteristics (amplitudes, time constants…) were similar to DC-RTS due to silicon bulk displacement damages in solid state imagers (CCD and CIS) exposed to high energy particles [15], and also to the DC-RTS recently observed in 3T-CIS-pixel conventional photodiode [16]. However, in PPD CIS, these centers are clearly located in the TG vicinity whereas they are located in the bulk or on the photodiode perimeter in the previous cases (irradiated imagers or 3T-pixel-CIS).…”

Frequency jumps in single chip microwave LC oscillators

“…8,9,15,21 Nowadays, the interest in the investigation of the RTS (and of related phenomena such as the bias temperature instability 10 ) is justified by its growing impact on the behavior of many electronic devices as their size is downscaled. 10 For example, the performance of image sensors 22,23 and memories 24,25 is highly influenced by these phenomena.…”