Enhancing Total-Ionizing-Dose Effects in the Partial Insulator in a Buried-Channel-Array Transistor: A Structural Proposal and Analytical Approach

In this paper, we present an analysis methodology for total ionizing dose (TID) effects in the partial insulator in a buried-channel-array transistor (Pi-BCAT) and demonstrate the superiority of the proposed structure. Previous research showed that the insertion of an insulator below the storage node in Pi-BCAT improved pre-irradiation gate-induced drain leakage (GIDL) and pre-irradiation row hammer effect (RHE) characteristics compared to the conventional buried-channel-array transistor (BCAT). However, under extreme environmental conditions, high-energy radiation could exacerbate TID effects, further worsening RHE and GIDL characteristics, which directly impacts the reliability of dynamic random-access memory applications, necessitating a thorough analysis of TID effects. In this study, we analyze the TID effects in BCAT and Pi-BCAT in terms of GIDL and RHE based on the gamma-ray dose penetrating the chip and propose the optimal package thickness for stable operation under different radiation doses. The proposed Pi-BCAT structure demonstrated a 63% improvement in leakage current performance and a similar reduction in TID-induced storage node voltage drop under 300-krad radiation compared to the conventional BCAT. Furthermore, the chip weight required to maintain equivalent TID reliability characteristics improved by ~90%.