Using Power Transform to Study the DC and AC Lifetime of High Temperature Hot-Carrier on 65 nm nMOSFETs

Autor: Ming-Xiu Wu, 吳明修
Rok vydání: 2010
Druh dokumentu: 學位論文 ; thesis
Popis: 98
It is well-known that hot-carrier (HC) reliability test is usually executed with constant voltage stress (CVS) to investigate MOSFET degradation in wafer foundry. Furthermore, the device lifetime (τ) is thus determined. It is a kind of acceleration test in order to shorten the tested time for evaluating the device yield. However, MOSFETs are always operated on AC mode in CMOS circuits. Thus, it is important to precisely find the suitable AC lifetime model for in-circuit devices. In this research, the tested devices were from 65 nm technology of United Micro-electronics Corporation (UMC). The device channel width/length (W/L) equal to 1/0.05 (μm/μm). Stress modes were set with DC and AC channel hot-carrier (CHC) conditions. All tests were conducted at temperatures of 25, 85, and 125oC. We propose a new way, power transform, that includes the voltage, current, and temperature, is used to find the AC lifetime of high temperature CHC. The DC and AC CHC test results show that the power transform model can describe device damage and is consistent with DC and AC stress data. In DC stress, the stress with the maximum stress voltage and the higher temperature causes the most severe device degradation. In AC stress, the stress signal with higher time period causes the most severe device degradation. We successfully predict device lifetime. Comparing the DC and AC lifetime prediction at operation region, all the results show AC CHC lifetime is better than DC CHC lifetime. The significance of this study is to clearly give wafer foundries and IC design houses the total transformed power (Ptotal) which causes device failure to understand the τ of in-circuit devices. It is not only to reduce the tested time, but also improve the work efficiency.
Databáze: Networked Digital Library of Theses & Dissertations
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