Radiation hardening by process technology for high voltage nMOSFET in 180 nm embeded flash process

Radiation-hardened embedded flash technology is widely used in aerospace field. The high voltage nMOSFET the key device to be hardened as it most sensitive total ionizing dose (TID) effect. In this study, shallow tench isolation (STI) sidewall implantation method harden 5 V for 180 nm eFlash process. Through study of TID response device, two problems emerge hardening technology. Firstly, ions are implanted after STI trench etching, doping profile influenced by following thermal process, resulting lower concentration at edge. fails work due leakage current 1×10<sup>5</sup> rad (1 = 10<sup>–2</sup> Gy) (Si) radiation. Secondly, that drain region reduce breakdown PN junction on side. Device cannot satisfy actual requirement circuit. To solve these problems, we propose a new called partial channel ion implantation. Comparing with previous method, order redistribution effect, adjust an extent oxidation gate oxide. Moreover, extra mask introduced determine avoid side device. Therefore, will not By using NMOS, can maintain typical design strip-type gate. compatible general process and does influence electrical parameters obviously. results show kept pico-ampere level 1.5×10<sup>5</sup> That five orders magnitude than obtained