Browsing by Author "HO, LT"

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A NEW DRAIN ENGINEERING STRUCTURE-SCD-LDD (SURFACE COUNTER DOPED LDD) FOR IMPROVED HOT-CARRIER RELIABILITY
(1993-09-01)
CHOU, JW
;
CHANG, CY
;
HO, LT
;
KO, J
;
HSUE, P
A new SCD-LDD (Surface Counter Doped LDD) structure is proposed. This structure introduces an additional oblique BF2 implant after nLDD implant, which counter-dopes the nLDD surface concentration near the gate edge. As a result, the lateral electric fields beneath the gate were reduced and the saturation drain current was conducted downward away from the maximum electric fields, resulting in a substantial enhancement of hot carrier reliability due to suppression of hot carrier generation and injection with this structure.
NEW LARGE-ANGLE TILT IMPLANTED DRAIN STRUCTURE - SURFACE COUNTER-DOPED-LIGHTLY DOPED DRAIN FOR HIGH HOT-CARRIER RELIABILITY
(1994-07-01)
CHOU, JW
;
CHANG, CY
;
HUANG, C
;
HO, LT
;
KO, J
A new surface counterdoped-lightly doped drain (SCD-LDD) structure with large angle tilt (LAT) implantation is proposed in this study. This structure introduces an additional larger tilt angle and lower-energy BF2 implant after the n- implant, which counterdopes the n- surface concentration to achieve a gate/n- fully overlapped, buried and sloped n- region inside the gate edge. As a result, the lateral electric fields inside the gate edge are reduced and pushed deeper into the substrate. In addition to a reduction in substrate current, this profile also suppresses hot carrier injection by driving the current away from the surface and the maximum electric field; then it shifts the avalanche region further into the bulk Si. This consequently produces a more effective enhancement of hot carrier reliability than that of conventional LDD's and controlled large-angle-tilt implanted drains (LATID's) for submicron VLSI circuits under 5 V operation. In conclusion, this SCD-LDD provides one more degree of freedom in optimizing the n- region doping profiles as a new LATID structure.