Testing and detection of aged integrated circuits based on testing embedded ADDS

Nowadays integrated circuits (ICs) lose its integrity because aged ICs are being recycled in the new products instead of fresh ICs. Replacing ICs potentially impacts the security and reliability of the electronic systems bound for military, financial and other critical applications. It is important to distinguish the aged ICs from the unused ones. The term aging implies the duration of IC in constant stress without interrupt. The method involves designing a sensor for detecting the characteristic degradation in IC, which occurs due to aging. The characteristics degradation mainly denotes the degradation in the threshold voltage of transistors when it is in continuous use. The method presents the degradation detecting sensor along with testing circuitry, which performs the operation of detecting the aged ICs as well as the fault that originates in the circuit. The sensor consists of ring oscillators, which contain chain of inverters along with control transistors. The sensor measures the degradation in the threshold voltage of transistors due to increasing in the number of interface traps that occurs due to aging. The increase in threshold voltage determined by means of the frequency difference of ring oscillators. Testing functions in sensor utilized with the help of control circuitry. By applying suitable test patterns, faults present in the circuit can be identified. Thus, the reliability of the IC is greatly enhanced.