For the first time, we propose a new ON current boosting technology for TFETs utilizing an isoelectronic trap (IET), which is formed by introducing electrically inactive impurities. We have demonstrated tunneling current enhancement by 735 times in Si-based diodes and 11 times enhancement in SOI-TFETs owing to non-thermal tunneling component by the Al-N isoelectronic impurity complex. The IET technology would be a breakthrough for ON current enhancement by a few orders in magnitude in indirect-transition semiconductors such as Si and SiGe.