Influence of Impurities and Microstructure on the Resistivity of LPCVD Titanium Nitride Films

Abstract

The electrical resistivity of LPCVD TiN films deposited at temperatures between 450 and 700°C has been found to vary from about 900 to 150 μ Ωcm. The elemental composition (Ti:N), impurity content and the microstructure of the films have been investigated in order to explain the resistivity variation. It appears that this variation is directly related to the chlorine (impurity) content of the films. Films deposited at 700°C have both the lowest chlorine content and the lowest value of resistivity. Additionally the difference between the resistivity of this latter film and the (lower) value for bulk TiN is discussed.

A Thermodynamic Analysis of Selective Area CVD of Titanium Nitride Compound by the Alternating Cyclic Method

“…The remaining variable, temperature, is constrained in terms of appropriate equilibrium constants for Eq. 1-8, which will be described subsequently Pt = PTICI4 + PTiC,3 + PTiC12 + P~C] + PN~ + PN~ + PHZ + PC,~ + PHCl + PH + PC, [11] P H --3pNH~ + 2PH2 + PHCl + PH --[12] PC, 4p~c14 + 3p~c13 + 2p~c12 + P~C~ + 2pc~2 + PC, + PHC] [13] 4p~cl4 + 3p~c13 + 2p~c,2 +P~c, + 2pc1~ +Pc1 +PHc, 4…”

Atom Probe Tomography investigations on grain boundary segregation in polycrystalline Ti(C,N) and Zr(C,N) CVD coatings

“…One plausible cause for such distinct behavior could be segregation of impurities at interfaces. For low temperature CVD processes, chlorine contamination is a concern [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] , which stems from the widely used metal chloride as a precursor in CVD reactions (e.g. TiCl 4 is the most widely used inorganic precursor employed in the CVD of titanium-containing materials (TiN, TiC, TiO 2 , Ti(C,N)) [22]).…”

“…Chlorine contamination related to CVD processes, using metal chloride precursors, is well known and documented for Low Temperature (LT) CVD processes; like Plasma Assisted (PA) [4][5][6][7][8][9][10][11][12][13]23,34] and Low Pressure (LP) CVD [12,[14][15][16][17][18][19][20][21]. However, its effects on MT-CVD process are underestimated or overlooked, given that chlorine content decreases considerably with higher temperatures and at MT-CVD temperature deposition range (700~950°C) the Cl concentration is very low.…”

“…For Ti(C,N) PA-CVD, Kim et al has shown that the chlorine content decreased largely with an increase of the temperature [6], and generally there is a consensus that the main parameter controlling the chlorine contamination in LT-CVD processes using metal chloride is the temperature [5,6,10,[13][14][15][16][17]20,21,23,34]. Some authors even controlled the chlorine contamination by changing only the temperature, while keeping the other parameters constant [13,23,34].…”

“…The absence of Cl segregation at these triple junctions is a strong evidence of the general absence of Cl at GBs in this coating. [15,16]. These conclusions were based on general correlations, e.g.…”