Synthesis and Selected Micro-Mechanical Properties of Titanium Nitride Thin Films by the Pyrolysis Of Tetrakis Titanium
- PDF / 883,193 Bytes
- 6 Pages / 414.72 x 648 pts Page_size
- 16 Downloads / 180 Views
RF
COIL
IDUCIONK-TYPE
THERMOCOUPLE
Figure 1 A schematic of
the CVD reactor used
in
"sitingTiN
depothin
films.
THROTTLING •"GRAPHITEVA SUSCEPTOR
OJMASS (
E
••
FLOW CONTROLLEREXAS
ELECTRO-PNEUMATIC VALVE
17 MECHANICAL PUMP
constant temperature of 323 K using a silicon oil bath with an immersion circulator. The vapor pressure of Ti((CH3 ) 2N) 4 at this temperature is -80 Pa. 5 Ultra-high-purity Ar (99.995 %, Alphagaz, Morrisville, PA) at 20 cm3/min (STP) was passed through the bubbler to carry the vapor into the reactor. The flow rate of ultra-highpurity NH3 (99.995 %, Alphagaz) was 300 cm3 /min (STP) which was separately fed into the reaction zone using a dual-path, co-axial injector constructed of inconel to prevent premature reaction with the Ti precursor. The concentration of the precursor in the initial gas mixture was estimated to be -1.2%. The distance between the tip of the injector and the leading edge of the substrate was -8 cm. The silicon substrates (1 cm x 1 cm) were placed on a 13-cm long graphite susceptor which was inductively heated by a radio-frequency generator (164 kHz). A K-type thermocouple which was in contact with the graphite susceptor was used to measure the deposition temperature. The deposition was carried out at 623 K and a pressure of 655 Pa. The films were characterized by means of Auger electron spectroscopy (AES) (PHI 650, Perkin Elmer, Eden Prairie, MN), X-ray diffraction (PAD V, Scintag, Sunnyvale, CA), transmission electron microscopy (TEM) (HF-2000, Hitachi, Tokyo, Japan), and
246
nanoindentation6 (Nano Instruments, Inc., Knoxville, TN). The friction coefficient of the MOCVD-TiN was determined by using a computer-controlled friction microprobe (FMP) .7 The slider material was a stainless steel ball (AISI 440C) with 1 mm diameter. Multiple-stroke tests were performed under ambient conditions with a normal force of 0.098 N, an average sliding velocity of 0.01 mm/s, and a stroke length of 0.42 mm. Details of the tribometer and friction coefficient measurement can be found elsewhere. 7 RESULTS AND DISCUSSION X-ray diffraction indicated that the deposits contained cubic TiN with a texture such that the (111) planes are preferentially aligned parallel to the surface of the substrate (Fig. 2). The preferred orientation persisted even after annealing at 943 K under vacuum for 1 h.
TIN CI!)
z
w
z a.
I0
Figure 2
20
30 40 28 (deree)
50
60
X-ray diffraction pattern of TiN deposited at 623 K and a system pressure of 655 Pa.
The TiN film was bright purple and uniform in color across the 1-cm2 silicon substrate. The deposition rate determined from the weight gain averaged -140 nm/min at 623 K (assuming the density of 3 TiN = 5.4 g/cm). Fig. 3 shows a typical AES spectrum of deposited TiN obtained after sputtering for 30 seconds with a 3.5-kV Ar÷ ion beam. The atomic ratio, estimated from peak-to-peak heights, indicated the formation of stoichiometric TiN. Carbon and oxygen were not observed. In contrast, TiN films prepared by other investigators contained significa
Data Loading...
