| 摘要 |
<p>PURPOSE:To inspect the charge amount of a floating gate in a positively charged state by measuring the amount of a current flowing in a dummy cell by taking out only the EEPROM part of the non-volatile RAM and providing it as the dummy cell. CONSTITUTION:In the state of positively charging a floating gate 16 of the dummy cell, a control gate 2 is set at a ground potential and a potential at an external terminal 8 is impressed. At such a time, since a transistor 13 for read is set in a conductive state, by making a select gate 3 H, a current flows from the external terminal 8 through the transistor 13 for read. However, since the amount of the current flowing through the transistor 13 depends on the amount of the charge stored in the gate 16, by investigating the amount of the current flowing from the external terminal 8, the amount of the charge stored in the gate 16 can be estimated.</p> |
