| 摘要 |
<p>PURPOSE:To forecast the degree of degradation of a memory transistor TR by providing a resistance element, which monitors the change of the extent of shift of a second threshold voltage of the memory TR, between the output of a sense amplifier and a power source. CONSTITUTION:If a memory TR M1 is turned on, the output of a sense amplifier 1 goes to a supply potential when the resistance value of a resistance element T12 provided between the output of the amplifier 1 and the power source is reduced, and the output of the amplifier 1 is switched to a prescribed potential lower than the supply potential when the resistance value is increased thereafter. When the extent of shift of a threshold voltage Vth of the TR M1 is large, the current driving capability is increased to quickly switch the output of the amplifier 1. Consequently, the time required for switching is obtained to monitor the extent of shift of the negative threshold Vth of the memory TR M1, namely, the degree of degradation.</p> |
