Novel Circuit-Level Model for Gate Oxide Short and its Testing Method in SRAMs
Novel Circuit-Level Model for Gate Oxide Short and its Testing Method in SRAMs
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SRAM中栅氧化层短路的新型电路级模型及其测试方法
DOI：
10.1109/tvlsi.2013.2268984
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发表时间：
2014
影响因子：
2.8
通讯作者：
Chih
中科院分区：
文献类型：
--
作者：
Chen;M. Chao;Chih
随着MOSFET栅氧化层厚度的大幅度减小，栅氧化层短路(GOS)已成为先进工艺中的常见缺陷。然而，受GOS影响的MOSFET的行为是复杂的，很难在电路级别上进行准确的建模。本文首先利用CAD技术建立了受GOS影响的MOSFET的黄金模型，并指出了以往GOS模型的局限性和不准确性。接下来，我们提出了一种新的电路级GOS模型，它比以往的任何模型都能提供更高的直流特性精度，并且能够表示最小尺寸的GOS影响的MOSFET。此外，该模型还考虑了受GOS影响的MOSFET的电容变化，能够很好地模拟GOS的暂态特性，这在以前的工作中还没有讨论过。最后，利用本文提出的GOS模型，提出了一种新的SRAM GOS测试方法，该方法能够有效地检测出常规IDDQ测试和3月测试中经常漏掉的GOS缺陷。
Gate oxide short (GOS) has become a common defect for advanced technologies as the gate oxide thickness of a MOSFET is greatly reduced. The behavior of a GOS-impacted MOSFET is, however, complicated and difficult to be accurately modeled at the circuit level. In this paper, we first build a golden model of a GOS-impacted MOSFET by using technology CAD, and identify the limitation and inaccuracy of the previous GOS models. Next, we propose a novel circuit-level GOS model which provides a higher accuracy of its dc characteristics than any of the previous models and being is able to represent a minimum-size GOS-impacted MOSFET. In addition, the proposed model can fit the transient characteristics of a GOS by considering the capacitance change of the GOS-impacted MOSFET, which has not been discussed in previous work. Last, we utilize our proposed GOS model to develop a novel GOS test method for SRAMs, which can effectively detect the GOS defects usually escaped from the conventional IDDQ test and March test.