$YBa_2Cu_3O_{7-x}$ superconducting thin film were deposited on the MgO and $LaAlO_3$(100) single crystal substrate by Metal Organic Chemical Vapr Deposition (MOCVD) method. These films showed critical temperature($T_c$) about 90K, $T_c$ tail, and critical current density of more than $10^5$A/㎠ at 77K. These films had c-axis orientation normal to the substrate and grainular structure with 1∼2μm diameter grains. Bridge-type Josephson junction, which had 2∼6μm line width and length were fabricated by lithography and Ar ion mill. $T_c$ and $J_c$ are not degraded after Ar ion mill. Current-voltage(I-V) characteristic of these bridge under the microwave at 77K was studed. $I_c$ was always decreased inverse proportion to microwave power. When microwave are irradiated on the bridge at 77K, I-V charateristic showed constant voltage steps(shapiro steps) at the voltage, V=nhv/2e with integer n. Josephson junction was verified by shapiro steps which were observed previously. These detector had high responsibility at the potimum bias current defined as the bias current of the maximum voltage.
