# RHLP-18T: A Radiation-Hardened 18T SRAM with Enhanced Read Stability and Low Power Consumption
## 4 Conclusions  
In this paper, RHLP-18T, a radiation-hardened 18-transistor SRAM cell, was presented. The design was developed with the objectives of achieving high read stability, low static power consumption, and robustness against Single Event Upsets. Transient fault simulations were conducted using 90 nm CMOS technology to evaluate its performance in comparison with nine existing Radiation-Hardened-By-Design SRAM cells. The proposed RHLP-18T cell demonstrated superior performance in several key aspects: It achieved the highest Read Static Noise Margin, indicating exceptional read stability, and exhibited the lowest hold power consumption, reflecting high energy efficiency. In addition, it maintained a competitive level of SEU tolerance, as evidenced by its effective critical charge.  
These combined strengths enabled RHLP-18T to achieve the highest Figure of Merit among all of the evaluated designs, highlighting its balanced performance characteristics. This result suggests that RHLP-18T is a promising candidate for applications where high reliability and low power consumption are essential, such as in aerospace and spaceborne systems. However, these advantages are accompanied by certain trade-offs. Specifically, RHLP-18T exhibits longer read and write access times, along with a slightly reduced HSNM and WSNM, compared to some alternative designs. These limitations reflect a conscious design decision to prioritize read stability and static power efficiency over high-speed access and write robustness. However, these compromises severely limit its viability in high-speed memory applications, presenting a major obstacle that requires targeted design improvements.  
Conceptualization, H.-G.K. and S.-H.J.; methodology, H.-G.K.; validation, H.-G.K.; data curation, H.-G.K.; writing--original draft preparation, H.-G.K.; writing--review and editing, S.-H.J.; visualization, H.-G.K.; supervision, S.-H.J.; project administration, S.-H.J. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
Data Availability Statement: Data are contained within the article.  
The EDA Tool was supported by the IC Design Education Center, Republic of Korea.  
The authors declare no conflicts of interest.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline
**Structure** & **HSNM** & **RSNM** & **WSNM** & **Qc** & **RAT** & **WAT** & **Hold Power** & **FOM** \\
**Name** & **/mV** & **/mV** & **/mV** & **/fC** & **/ps** & **/ps** & **/nW** & **FOM** \\ \hline RHBD-14T & 240 & 49 & 450 & 17.4 & 59.97 & 18.19 & 29.23 & 2.89 \\ HPHS-12T & 173 & 11 & 478 & 9.29 & 41.8 & 18.9 & 40.49 & 0.26 \\ NRHC-14T & 153 & 30 & 422 & \(>\)50 & 50.69 & 9.87 & 23.12 & 8.37 \\ QCCS-12T & 278 & 27 & 439 & 11.6 & 56.28 & 11.7 & 51.11 & 1.14 \\ RHMC-12T & 196 & 10 & 463 & 12 & 84.41 & 24.75 & 25.69 & 0.2 \\ RHWC-12T & 281 & 27 & 437 & 11.61 & 56.28 & 11.76 & 51.11 & 1.14 \\ SEA-14T & 222 & 18 & 376 & \(>\)50 & 143.63 & 44.3 & 47.74 & 0.25 \\ SIMR-18T & 137 & 18 & 459 & \(>\)50 & 156.99 & 34.26 & 3.07 & 3.43 \\ SERSC-16T & 211 & 1 & 302 & 11.25 & 118.45 & 10.94 & 66 & 0.01 \\ This work & 173 & 150 & 305 & 37.83 & 105.09 & 46.68 & 2.72 & 22.44 \\ \hline \end{tabular}
\end{table}
Table 1: Performance comparison between the RHLP-18T cell and other radiation-hardened SRAM cell structures.