Hostname: page-component-8448b6f56d-sxzjt Total loading time: 0 Render date: 2024-04-23T08:22:31.164Z Has data issue: false hasContentIssue false
  • English
  • Français

Morphology and Electrical Properties of Pure and Ti-Doped Gas-Sensitive Ga2O3 Film Prepared by Rheotaxial Growth and Thermal Oxidation

Published online by Cambridge University Press:  03 March 2011

Chin-Cheng Chen  and
Chiu-Chen Chen
Chin-Cheng Chen*
Affiliation:
Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan, Republic of China
Chiu-Chen Chen
Affiliation:
Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan, Republic of China
*
a)Address all correspondence to this author. e-mail: ccchen@mail.ncku.edu.tw
Get access

Abstract

An n-type Ga2O3 semiconductor thin film was prepared by rheotaxial growth and thermal oxidation (RGTO) method on SiO2 and Al2O3 substrates. Multilayer growth technique was used to control grain size. The morphology and the electrical properties of the Ga and Ga2O3 films were measured as functions of thickness, temperature, and Ti dopant concentration. Measurements of the sensitivity, the response time, and the recovery time of the Ga2O3 films in response to ethanol and CO were carried out.The results showed that the grain size of Ga film increased with thickness, and a balls-on-ball type morphology was produced as the film exceeded 3000 Å. Ga2O3 nanowires were created when Ga films were oxidized under impure O2 atmosphere. Ga2O3 films had an optimum sensing temperature increasing from 625 °C for a5012 Å film to 675 °C for a 5.6-μm film. The films prepared by multilayer growth technique had smaller grain size, but the sensitivity remained unchanged. The films deposited on SiO2 substrate had a sensitivity higher by 28% than that on Al2O3. Doping of 0.28 at.% Ti enhanced nanowires growth, raised sensitivity by 6%, shortened response time from 40 to 30 s, but prolonged recovery time from 92 to130 s. Formation of nanowires resulted in an increase of sensitivity up to 50%.Doping of 2.18 at.% Ti led to the formation of nanoribbons with a sensitivity lowerby 8% and a recovery time shortened from 130 to 72 s. The RGTO method was shown to produce Ga2O3 gas-sensitive thin film with good reproducibility.

Keywords

SensorSemiconductorPhysical vapor deposition (PVD)
Type
Articles
Information
Journal of Materials Research , Volume 19 , Issue 4 , April 2004 , pp. 1105 - 1117
Copyright
Copyright © Materials Research Society 2004

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1Walsh, P.T.Toxic gas sensors for occupational health and safety, Transducer Technology, 13, (Feb. 1990)Google Scholar
2Weisz, P.B.: Effects of electronic charge transfer between adsorbate and solid on chemisorption and catalysis. J. Chem. Phys. 21, 1531 (1953).Google Scholar
3Seiyama, T., Kato, A., Fujiishi, K. and Nagatani, M.: A new detector for gaseous components using semiconducting thin films. Anal. Chem. 34, 1502 (1962).CrossRefGoogle Scholar
4Shaver, P.J.: Activated tungsten oxide gas detectors. Appl. Phys. Lett. 11, 255 (1967).CrossRefGoogle Scholar
5Rosenfeld, D., Sanjines, R., Schreiner, W.H. and Levy, F.: Gas sensitive and selective SnO2 thin polycrystalline films doped by ion implantation. Sens. Actuators B. 15-16, 406 (1993).Google Scholar
6Lin, H.M., Hsu, T.Y., Tung, C.Y. and Hsu, C.M.: Hydrogen sulfide detection by nanocrystal Pt doped TiO2 base gas sensors. Nanostructured Mater. 6, 1001 (1995).Google Scholar
7 J. Frank, M. Fleischer, and H. Meixner: Electrical doping of gas-sensitive, semiconducting Ga2O3 thin films, The 8th International Conference on Solid-State Sensors and Actuators and Eurosensors IX, Stockholm, Sweden: Foundation for Sensor and Actuator Technology: Copies Available from the Royal Swedish Academy of Engineering Sciences, IVA, June 25-29, pp. 850–853 (1995).Google Scholar
8Gopel, W. Chemical sensor technologies: Empirical art and systematic research in Sensors: A Comprehensive Survey, Chemical Sensor Technologies: Empirical Art and Systematic Research in Sensors: A Comprehensive Survey , edited by Gopel, W., Hesse, J., and Zemel, J.N. 2, (VCH, New York, 1991), p. 61Google Scholar
9Xu, C., Tamaki, J., Miura, N. and Yamazoe, N.: Correlation between gas sensitivity and crystallite size in porous SnO2-based sensors. Chem. Lett. 3, 441 (1990).CrossRefGoogle Scholar
10Morrison, S.R.: Chemical Sensors in Semiconductor Sensors , edited by Sze, S.M. (John Wiley & Sons, New York, 1994), p. 383Google Scholar
11Fleischer, M. and Meixner, H.: Sensing reducing gases at high temperatures using long-term stable Ga2O3 thin films. Sens. Actuators B. 6, 257 (1992).CrossRefGoogle Scholar
12Roy, R., Hill, V.G. and Osborn, E.F.: Polymorphism of Ga2O3 and the system Ga2O3-H2O. J. Am. Chem. Soc. 74, 719 (1952).Google Scholar
13Geller, S.: Crystal structure of -Ga2O3. J. Chem. Phys. 33, 676 (1960).CrossRefGoogle Scholar
14Gourier, D., Binet, L. and Aubay, E.: Magnetic bistability and memory of conduction electrons released from oxygen vacancies in gallium oxide. Radiation Effects and Defects in Solids. 134, 223 (1995).CrossRefGoogle Scholar
15Kohn, J.A., Katz, G. and Broder, J.D.: Characterization of -Ga2O3 and its alumina isomorph, -Al2O3. Am. Mineral. 42, 398 (1957).Google Scholar
16Fleischer, M. and Meixner, H.: Electron mobility in single-and polycrystalline Ga2O3. J. Appl. Phys. 74, 300 (1993).Google Scholar
17Cojocaru, L.N. and Alecu, I.D.: Electrical properties of -Ga2O3, Zeitschrift fur Physikalische Chemie Neue Folge. Bd. 84, 325 (1973).Google Scholar
18Harwig, T., Wubs, G.J. and Dirksen, G.J.: Electrical properties of -Ga2O3 single crystals. Solid State Commun. 18, 1223 (1976).CrossRefGoogle Scholar
19Kofstad, P.: Defect Reactions in Nonstoichiometry, Diffusion and Electrical Conductivity in Binary Metal Oxides (Wiley-Interscience, New York, 1972) p. 15Google Scholar
20Kroger, F.A.: Detailed Description of Crystalline Solids; Imperfections in The Chemistry of Imperfect Crystals , (North Holland, New York; American Elsevier, 1974), p. 1Google Scholar
21Fleischer, M., Hanrieder, W. and Meixner, H.: Stability of semiconducting gallium oxide thin films. Thin Solid Films. 190, 93 (1990).Google Scholar
22Sberveglieri, G., Faglia, G., Groppelli, S., Nelli, P. and Camanzi, A.: A new technique for growing large surface area SnO2 thin film (RGTO technique). Semicond. Sci. Technol. 5, 1231 (1990).Google Scholar
23Watson, J.: A note on the electrical characterization of solid-state gas sensors. Sens. Actuators B. 8, 173 (1992).Google Scholar
24Sondheimer, E.H.: The mean free path of electrons in metals. Adv. In Phys. 1, 1 (1952).Google Scholar
25Berry, R.W., Hall, P.M. and Harris, M.T.: Electrical Conduction in Metals in Thin Film Technology (Van Nostrand, New York, 1968), p. 289Google Scholar
26Doherty, R.D.: Dendritic Growth in Crystal Growth, edited by Pamplin, Brian R. (Pergamon, New York, 1980), p. 485Google Scholar
27Hill, V.G., Roy, R. and Osborn, E.F.: The system alumina-gallia-water. J. Am. Ceram. Soc. 35, 135 (1952).CrossRefGoogle Scholar
28Hoefer, U., Frank, J. and Fleischer, M.: High temperature Ga2O3-gas sensors and SnO2-gas sensors: A comparison. Sens. Actuators B. 78, 6 (2001).CrossRefGoogle Scholar
29Kohl, D.: Surface processes in the detection of reducing gases with SnO2-based devices. Sens. Actuators B. 1, 158 (1990).Google Scholar
30Frank, J., Fleischer, M. and Meixner, H.: Gas-sensitive electrical properties of pure and doped semiconducting Ga2O3 thick films. Sens. Actuators B. 48, 318 (1998).CrossRefGoogle Scholar
31Kiss, G., Pinter, Z., Perczel, I.V., Sassi, Z. and Reti, F.: Study of oxide semiconductor sensor materials by selected methods. Thin Solid Films. 39, 216 (2001).CrossRefGoogle Scholar
32Fleischer, M.M. and Meixner, H.: Improvements in Ga2O3 sensors for reducing gases. Sens. Actuators B. 13-14, 259 (1993).CrossRefGoogle Scholar
33Flingelli, G.K., Fleischer, M.M. and Meixner, H.: Selective detection of methane in domestic environments using a catalyst sensor system based on Ga2O3. Sens. Actuators B. 48, 258 (1998).Google Scholar
34Reti, R., Fleischer, M., Perczel, I.V., Meixner, H. and Giber, J.: Detection of reducing gases in air by -Ga2O3 thin films using self-heated and externally(oven-) heated operation modes. Sens. Actuators B. 34, 378 (1996).CrossRefGoogle Scholar