Simulation of threshold voltage adjustment by B+ implantation for pMOS-RADFET application

pMOS-RADFET (radiation field-effect transistor) as micro-dosimeter has been widely applied in spacecraft, medicine and personnel dosimetry. Thick gate-oxide and zero threshold voltage (V_th) are two critical factors to achieve high performance pMOS-RADFET. In this paper, the V_th adjustment techniques for thick gate oxide by B⁺ implantation are simulated systematically by Silvaco TCAD, including implanting energy, dose and annealing conditions. And the impurity distributions both in gate-oxide and silicon substrate are analyzed. The results show that implanting energy up to 130keV and dose as 3.2e11 works well for 388nm gate-oxide. Considering activation and distribution of impurity, both annealing temperature and time has to be as low and short as possible.