Rapid thermal anneal of gate oxides for low thermal budget TFT's

The performance and reliability of deposited gate oxides for thin film tran sistors (TFT's) has been studied as a function of rapid thermal annealing ( RTA) conditions. The effect of temperature ranging from 700 to 950 degrees C and the annealing ambients including oxygen (O-2), argon (Ar), and nitrou s oxide (N2O) is investigated. Improvement in charge to breakdown (Q(bd)) i s seen starting from 700 degrees C, with marked increase at 900 degrees C t emperature and above. The N2O and Ar ambients result in higher Q(bd) compar ed to O-2 ambient and we attribute this to reduced interfacial stress, Four ier Transform Infrared spectroscopy (FTIR) is used to qualitatively measure the stress, The bias temperature instability is decreased by RTA, The TFT characteristics are significantly improved with RTA gate oxide. The RTA-Ar anneal at 950 degrees C results in the lowest trap density in TFT's as meas ured from charge pumping technique.