Gate length dependence of the shallow trench isolation leakage current in an irradiated deep submicr

• 作 者: 刘张李 胡志远 张正选 邵华 陈明 毕大炜 宁冰旭 邹世昌
• 机 构: State Key Laboratory of Functional Materials for Informatics,Shanghai Institute of Microsystem and I
• 出 处: 半导体学报
• 发表日期: 2011年06期
• 关键词: leakage trench shallow transistor irradiated irradiation drain isolation negligi

The effects of gamma irradiation on the shallow trench isolation(STI)leakage currents in a 0.18μm technology are investigated.NMOSFETs with different gate lengths are irradiated at several dose levels.The threshold voltage shift is negligible in all of the devices due to the very thin oxide thickness.However,an increase in the off-state leakage current is observed for all of the devices.We believe that the leakage is induced by the drain-to-source leakage path along the STI sidewall,which is formed by the positive trapped charge in the STI oxide.Also, we found that the leakage is dependent on the device’s gate length.The three-transistor model(one main transistor with two parasitic transistors)can provide us with a brief understanding of the dependence on gate length.

The effects of gamma irradiation on the shallow trench isolation (STI) leakage currents in a 0.18 μm technology are investigated. NMOSFETs with different gate lengths were irradiated at several dose levels. The threshold voltage shift is negligible in all of the devices due to the very thin oxide thickness. Since an increase in the off-state leakage current is observed for all of the devices. We believe that the leakage is induced by the drain-to-source leakage path along the STI sidewall, which is formed by the positive trapped charge in the STI oxide. Also, we found that the leakage is dependent on the device’s gate length. The three-transistor model (one main transistor with two parasitic transistors) can provide us with a brief understanding of the dependence on gate length.