Abstract: A charge measuring device detects focused ion beam attacks on an integrated semiconductor circuit with a capacitor, a field effect transistor, and a charge collecting device all manufactured in the integrated semiconductor circuit and insulated from additional circuit elements. A first pole of the capacitor is conductively connected to the charge collecting device and a gate of the field effect transistor. When a voltage is applied to the second pole of the capacitor, a drain source current flows through the field effect transistor, and a relationship between the voltage and the drain source current is ascertained. A comparison of the relationship with a previously ascertained relationship indicates a change of the charge quantity stored in the capacitor by the charge collecting device.

Abstract: A charge measuring device detects focused ion beam attacks on an integrated semiconductor circuit with a capacitor, a field effect transistor, and a charge collecting device all manufactured in the integrated semiconductor circuit and insulated from additional circuit elements. A first pole of the capacitor is conductively connected to the charge collecting device and a gate of the field effect transistor. When a voltage is applied to the second pole of the capacitor, a drain source current flows through the field effect transistor, and a relationship between the voltage and the drain source current is ascertained. A comparison of the relationship with a previously ascertained relationship indicates a change of the charge quantity stored in the capacitor by the charge collecting device.