Plasma-enhanced chemical vapor deposition (PECVD) method is widely used for thin-film deposition of insulating and semiconducting layers in thin-film transistors (TFT) for active-matrix liquid-crystal display (AMLCD) and active-matrix organic light-emitting diode (AMOLED) displays. The basic guideline for scaling up PECVD processes generation to generation has been to maintain the same intensive deposition parameters, such as substrate temperature, deposition pressure, and electrode spacing, while somewhat proportionally increasing the extensive deposition parameters such as radio frequency (RF) power and gas flow rate. All modern PECVD chambers are also equipped with in situ dry cleaning capability in the form of a remote plasma source cleaning (RPSC) unit. RPSC technology created a second productivity revolution in mass production PECVD tools due to further improvements in particles and yield performance, as well as enabling a longer lifetime of process chamber components such as diffusers and susceptors.

An inlet gas manifold for a vacuum deposition chamber incorporates inlet apertures which increase in diameter or cross-section transverse to the direction of gas flow. The aperture configuration increases the dissociation gases such as nitrogen and, thus increases the rate of silicon nitride deposition provided by nitrogen gas chemistry, without requiring the use of reactants such as ammonia. While one could use ammonia in the depo sition gas chemistry if desired, the process provides the option of completely eliminating ammonia. The inlet manifold containing the increasing-diameter gas inlet holes provides enhanced control of the process and the deposited film, and is also useful for forming other di electrics such as silicon oxide and silicon oxynitride. In particular, silicon oxynitride films are characterized by low hydrogen content and by compositional unifor mity.

To enhance our understanding of the therm al interactions of fluorocarbons with transition-metal surfaces, C F3I was adsorbed on clean and iodine-precovered A g ( l l l ) and studied by temperature-programmed desorption (TPD), X -ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (U PS), and Auger electron spectroscopy (AES). On clean A g(l 1 1) a t 105 K, dissociative adsorption dominates a t low coverages and molecular adsorption a t high coverages. Dissociation involves C -I bond cleavage; there is no evidence for C -F cleavage, even during TPD. W hile m ultilayer desorption peaks near 118 K, chemisorbed C F3I desorbs in a sharp peak a t 126 K with a high-tem perature shoulder near 145 K. The only other detectable desorption products are C F 3(g) and 1(g), which desorb a t 300 and 830 K, respectively. In the presence of low coverages of 1(a), less C F 3 and more C F3I desorbs. W hen the surface I /A g ratio is 0.33 ( V 3 X * \/3R30° structure), the dissociation channel is completely suppressed. The influence of atomic iodine is discussed in term s of combined electronic and site blocking effects.

Possible mechanisms to achieve high mobility in zinc oxynitride (ZnON) have been investigated by comparison with other thin film semiconductors. Integrated processes to fabricate ZnON TFTs have been developed. Issues and challenges encountered at current stage will be discussed.