Characterization Of Ta Thin Films Obtained By Dc Sputtering

We have studied thin films of Ta deposited by dc sputtering on amorphous (glass) and crystalline substrates ((100) and (111)Si wafers.) Optimum deposition conditions were established for (4 × 9) cm2 glass substrates with respect to resistivity and thickness uniformity: 1700 V, target-to-substrate distance 25 mm and pressure 60 mtorr. The deposition thus obtained was 280 Å min-1 and the resistivity 2.4 × 10-3 ω cm. X-ray diffraction analysis showed that the 1600 nm films had bcc structure, with a strong (110) preferential orientation, and grain sizes smaller than 100 Å. The density of the films was 12.4(±0.3) g cm-3. SEM analysis showed they present a columnar growth. The results are being compared with Ta films from the University of Stuttgart, where they are normally used for TFTs. These films of 260 nm deposited by rf sputtering on a 200 nm TaO5 layer (thermally grown) have also been identified as having a bcc structure and small grain size. © 1990.414-614031404Lueder, Kallfass, Frash, Schaible, (1982) SID 82 Digest, p. 186Silveira, Mammana, (1990) Vacuum, 41, p. 1390Maissel, Glang, (1970) Handbook of Thin Film Technology, , McGraw-Hill, New YorkSchuetze, Ehlbeck, Doerbeck, (1963) Trans 10th Natl Vacuum Symp, p. 43