A New LDD Structure: Total Overlap with Polysilicon Spacer (TOPS)

J. E. Moon, T. Garfinkel, J. Chung, M. Wong, P. K. Ko, Chen-Ming Hu

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


This letter presents a new fully overlapped lightly doped drain structure—the total overlap with polysilicon spacer (TOPS) structure. The TOPS structure achieves full gate overlap of the lightly doped region with simple processing. TOPS devices have demonstrated superior performance and reliability compared to oxide-spacer lightly doped drain (LDD) devices, with an order of magnitude advantage in current degradation under stress for the same initial current drive or 30% more drive for the same amount of degradation. TOPS devices also show a much smaller sensitivity to n− dose variation than LDD devices. Gate-induced drain leakage (GIDL) is reported for the first time in fully overlapped LDD devices.

Original languageEnglish
Pages (from-to)221-223
Number of pages3
JournalIEEE Electron Device Letters
Issue number5
StatePublished - 1 Jan 1990

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