The Effect of Grain Boundary Diffusion on the Boundary Structure and Electrical Characteristics of Semiconductive <tex>$SrTiO_3$</tex> Ceramics

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J. Korean Ceram. Soc. > Volume 34(1); 1997 > Article

Journal of the Korean Ceramic Society 1997;34(1): 23.

입계확산에 의한 반도성 $SrTiO_3$ 세라믹스의 입계구조 및 전기적 특성 변화

김태균, 조남희

인하대학교 무기재료공학과

The Effect of Grain Boundary Diffusion on the Boundary Structure and Electrical Characteristics of Semiconductive $SrTiO_3$ Ceramics

ABSTRACT

Semiconductive SrTiO3 ceramic bodies were prepared by conventional ceramic powder processes in-cluding sintering in a reducing atmosphere. Sodium or potassium ions were diffused from the surface of the sintered bodies into the inner region using thermal diffusion process at 800-120$0^{circ}C$. The effects of such ther-mal treatments on the electrical and chemical characteristics of the grain boundaries were investigated. The presence of sodium or potassium ions at grain boundaries produces non-linear current-voltage behaviors, electrical boundary potential barriers of 0.1-0.2eV, and threshold voltages of 10-70V. The diffused ions form diffusion layers with thicknesses of 20-50nm near the grain boundaries, reducing the concentration of strontium and oxygen.

Key words: $SrTiO_3$, Semiconductive, Potential barrier, Diffusion layer