Correction of Single Event Latchup Rate Prediction Using Pulsed Laser Mapping Test

Abstract

Most classical approaches of single event effect rate prediction are based on the rectangular parallelepiped model of sensitive volume. However it is not clear about the number of sensitive volume in the device when predicting the in-flight single event latchup rate. As for memory device, there are two empirical practices to deal with the latchup sensitive volume number: one assumes that there is only one sensitive volume in the whole device; another assumes that there are as much sensitive volumes as the number of memory cells. The latchup sensitive volume number of a 4M-bits SRAM is determined as 63360 using pulsed laser mapping test in this work first. Based on the two assumed and measured sensitive volume number, the single event latchup rates of the device are calculated and compared. The results show that pulsed laser could be a powerful tool to obtain the real sensitive volume number in the device, which is significant for single event latchup rate prediction. The latchup rate will be either overestimated or underestimated with the assumption of the sensitive volume number as one or as much as the number of memory cells.Index Terms-In-flight rate, pulsed laser, sensitivity mapping, single event latchup (SEL), SRAM.

The Pion Single-Event Latch-Up Cross Section Enhancement: Mechanisms and Consequences for Accelerator Hardness Assurance

“…The sensitive size for the memory in the model was derived from the observations on SEL induction regions achieved on SRAM structures of 180 nm [21] performed with laser testing, which was proven to provide reliable results for proton and neutrons [9]. Laser testing was shown to be a valuable complementary tool in the qualification process of integrated circuits as it can enable determining the characteristics of the sensitive volume such as the size [21,22], and the thickness [23] as well as to correlate it with the heavy ion response for determining the LET threshold [24], the cross-section [25] or even the number of sensitive cells within the device [26]. All this information can be used to retrieve a better estimation of expected SEL rates in application.…”

Simplified SEE Sensitivity Screening for COTS Components in Space

“…For SEL the SV dimensions are considered as 20 x 4 x 2 µm 3 according to laser studies of similar technologies [16]. Indeed, 2 µm is the standard SV thickness used in recent in-flight SEL rate studies [17], [18] however as will be later discussed should not be applied as a general reference value. For SEU, we assume an SV volume of 3 x 3 x 0.5 µm 3 according to the cell size of the considered SRAM and the associated estimated charge collection depth.…”

Application of Two-Photon-Absorption Pulsed Laser for Single-Event-Effects Sensitivity Mapping Technology

“…Pulsed laser systems have been introduced and widely used for simulating Single Event Effects procedure by generating EHPs through photon-particle interaction [4,5,6]. For SRAM and Flip-Flop cells, laser systems can be used to find the sensitive area [7,8,9,10]. Due to the ability of changing focus length, a 3-D SEEs profile can be also achieved by laser systems [11,12].…”

“…To obtain SEEs sensitive mapping by laser system is an interesting researching area. There are some studies related on SEEs mapping for commercial SRAM chips [7,8,9]. However, the dimension of these commercial SRAM cells are mostly several micrometers, and the structures of them are not hardened against radiation [23].…”