Studies of the LDD Process for HCE Improvement

The hot carriers is due to the acceleration, and a carrier having a large kinetic energy generated by impact ionization in the channel electric field . Hot carriers injected into the gate oxide layer of a certain probability of formation of interface states . The interface state charge capture the device characteristics recession . With the shrinking size of devices , hot carrier effects will become more and more serious . The device characteristics recession can also cause lower circuit and even the life of the product , hot carrier effects (HCE) has become one of the main failure mechanism of the long-term reliability of MOS circuits . Gate oxide fluoride or nitride and lightly doped drain (LDD) process are commonly used method to improve hot carrier effects fluoride on gate oxide or nitride and LDD process of deep submicron devices heat the carrier effect the study was commenced . The results show , through the gate oxide layer fluoride or nitride and optimize the LDD process can significantly improve heat carrier effect of the MOS device . The mechanism of improvement are : to improve gate oxide layer line hot carrier injection capability , and decreases the channel electric field strength and make the collision ionization zone away from the silicon substrate - the gate oxide layer interface .