AVS 49th International Symposium
    Thin Films Wednesday Sessions
       Session TF+VT-WeM

Invited Paper TF+VT-WeM6
Alternating Layer Deposition of Dielectric Films

Wednesday, November 6, 2002, 10:00 am, Room C-101

Session: Atomic Layer Deposition - Barriers & Nitrides
Presenter: A.P. Paranjpe, TORREX
Authors: A.P. Paranjpe, TORREX
B. McDougall, TORREX
K.Z. Zhang, TORREX
W. Vereb, TORREX
Correspondent: Click to Email
Interest in alternating layer deposition (ALD) for the deposition of thin films used in semiconductor devices has grown rapidly due to the numerous advantages offered by ALD. Often, relatively high exposure doses are required to achieve self-limited surface saturation that is necessary for good uniformity, conformal deposition in high aspect ratio features, low impurity incorporation, and superior electrical properties. The low deposition rates make ALD using conventional reactors impractical in a semiconductor manufacturing environment for film thickness values > 10 nm. We describe a Parallel Wafer Processing reactor architecture capable of processing 1 - 25 wafers simultaneously that provides a 3X - 4X throughput advantage over single wafer ALD processes for both standalone and clustered operation. This reactor architecture is well-suited for the deposition of SiN and SiO@sub 2@, since initial surface chemisorption rates are relatively high, but high exposures (> 10 Torr-s) are required to achieve self-limited surface saturation. Exceptionally smooth (Ra < 0.15 nm), stoichiometric SiN films with conformality of ~ 100% in high aspect ratio features can be deposited at 0.1 - 0.2 nm/cycle in the temperature range of 450 - 550°C. The hydrogen content and wet etch rates are significantly lower than CVD SiN films deposited at equivalent temperatures confirming that ALD provides superior film quality. Electrical leakage is lower compared to SiN deposited in a conventional furnace at 750°C. SiN films have also been deposited via cyclic CVD which is analogous to ALD except that the chemisorption of the Si source deviates from the ideal self-limited behavior. Cyclic CVD offers deposition rates that are up to 50% higher than deposition rates achievable in ALD, but film properties including conformality are intermediate between ALD and CVD films. We will also discuss the deposition of other dielectric films using the Parallel Wafer Processing reactor.