The electrical conductivity of thick film $SrTiO_3$ which has been prepared by screen printing and sintering was determined for the oxygen partial pressure range of $10^0$ to $10^{-20}$ atm and temperature range of 900 to 1100℃. The data were found to be proportional to the -1/4th power of the oxygen partial pressure for the oxygen pressure range about $10^{-4}\sim10^{-8}$ to $10^{-20}$ atm and proportional to $Po_2,^{+1/4}$ for the oxygen pressure range $10^{-6} \sim10^{-4}$ to $10^0$ atm according to measureing temperture. And the p-n transition region of electrical conductivity moved to higher oxygen partial pressure range as the sintering temperature of thick film specimens increased at about below 1400℃.
These data are consistent with the presence of small amounts of acceptor impurities in thick film $SrTiO_3$ which have been permeated from $Al_2O_3$ substrate in the range of solid solubility limits. WDX analyses of interfacial regions have been performed for confirmation of the presence of acceptor impurities in $SrTiO_3$ films. The response time of thick film $SrTiO_3$ had better characteristics than bulk $SrTiO_3$.
