Relationship Between the Process Parameters and Film Properties of “Low Temperature” Low Pressure Chemical Vapor Deposition Titanium Nitride Films

Abstract

Titanium nitride is deposited from the reactants TIC14 and NH3, with Ar as a diluent gas. These depositions are carried out in a commercial cold wall single wafer reactor, equipped with a load lock and a HF cleaning module for the removal of native oxide. The influence of the TIC14 partial pressure on the TiN film properties and the growth rate is investigated. After an initial rise at low TIC14 partial pressure, the growth rate decreases with increasing TIC14 partial pressure. The decreasing deposition rate is caused by the presence of the complex forming reactions in the gas phase. During these depositions less than 5 % TiCl4 is consumed by the TiN deposition. However, high conversion fractions of the TiCl4 (> 15 %) are observed during the initial rise of the deposition rate at low TIC14 partial pressures. A shift from the diffusion controlled region to the reaction controlled region seems to take place. This shift compares with a change in the film properties. The films deposited in the reaction controlled region are yellow gold colored. They all have the same film properties, i.e., a resistivity of 120 ~If~ 9 cm • i0 ~If~ 9 cm, chlorine concentration of 0.7 atom percent (a/o), contain no detectable amounts of oxygen and are preferential (200) orientated. The films deposited in the diffusion controlled region are dull reddish/brown and have higher values of the resistivity. These films show more randomly oriented grains and contain no detectable amounts of chlorine. However, in contrast with the former TiN films, these films contain about 5 a/o oxygen. The microstructure and the related surface roughness determine the visual appearance of these films.TiN coatings are widely used in several technological applications due to their hardness, gold color, high melting point, good thermal and electrical conductivity, and corrosion resistance. '-4 TiN films as diffusion barriers are an important application in the IC industry. 24 Conventionally, these TiN films are deposited by reactive sputtering 4 or by nitriding of sputtered titanium layers. 5 However, as IC feature sizes shrink to sub-micron dimensions, the ability of physical techniques, such as sputtering, to coat uniformly high aspect ratio vias has become a concern. Replacing the physical technique by chemical vapor deposition (CVD) is an alternative to circumvent this problem. Deposition of low pressure CVD (LPCVD) TiN with conformal step coverage is possible with TiCl4 and NH3 as reactants. ~'7 It has already been shown that in a contact hole with aspect ratio of 1.9 a step coverage of 100% can be achieved. ~ However, TiN films deposited with these reactants contain more than 2 atom percent (a/o) chlorine at deposition temperatures below 550~A disadvantage of the chlorine contamination is the corrosive nature of this element, e.g., in combination with aluminum, which might shorten the life time of an IC. An increasing amount of chlorine gives also a higher film resistivity. 8 Other TiN film properties, influencing the resistivity are the oxygen contaminatio...

Correlation Between the Electrical Properties and the Morphology of Low-Pressure MOCVD Titanium Oxynitride Thin Films Grown at Various Temperatures

“…Titanium nitride has been widely studied over the past several years, and different chemical and physical deposition techniques have been used in the production of such films for applications in protective coatings, [1] electrical contacts, [2] and diffusion barriers. [3,4] Moreover, the presence of oxygen in titanium nitride films leads to a promising functional range of materials, TiN x O y , already used as solar selective absorbers, [5] or transparent windows for infrared detectors.…”

Study on plasma assisted metal-organic chemical vapor deposition of Zr(C,N) and Ti(C,N) thin films and in situ plasma diagnostics with optical emission spectroscopy

“…5,6 However, chlorine impurity in the as-grown films and relatively high deposition temperature ͑Ͼ600°C͒ are considered major drawbacks for actual device fabrication. The most widely used precursors for ZrN and TiN film growth are ZrCl 4 and TiCl 4 , and these processes usually provide good film quality and excellent step coverage.…”

Optimization of the Deposition Conditions of Titanium Nitride from Ammonia and Titanium Tetrachloride

“…This can be achieved by conventional thermal CVD using less stable molecules such as organometallic compounds or ammonia for the nitrogen precursor. The TiCl4-NH3-H2 mixture has been used by several authors to deposit at low temperature TiN films either for thermomechanical applications [2][3][4] or as diffusion barrier [5][6][7][8]. This paper is intended to optimize the deposition conditions of titanium nitride films on molybdenum substrate from a titanium tetrachloride, ammonia, nitrogen and hydrogen gas mixture.…”