Dai Hisamoto

A new soft-error phenomenon in VLSIs: the alpha-particle-induced source/drain penetration (ALPEN) effect

The alpha-particle source/drain penetration (ALPEN) effect is investigated using a 3-D device simulator (CADDETH) and a novel experimental method. A study of soft error due to alpha-particle injection has so far focused on such memory structures and circuits as DRAMs/SRAMs. However, a new soft error is expected to occur in single MOSFETs as the effective channel length becomes comparable to the funneling length. The authors describe: (1) the funneling penetration current between source and drain; (2) a new soft error (0 to 1) caused by the ALPEN effect; (3) experimental verification of the ALPEN effect; and (4) the impact on VLSI scaling. The ALPEN effect puts various constraints, such as the latch-up, emitter-to-collector short in bipolars, and punchthrough in parasitic MOSFETs, on VLSI design. Thus, the ALPEN effect will be a crucial factor in the scaling limits of future ULSIs with dimensions below 0.5 mu m. >

Evidence for ballistic transport of two‐dimensional electron gas at liquid‐nitrogen temperatures in a silicon metal–oxide semiconductor field effect transistor with a neck in the middle

The transconductance of a silicon metal–oxide semiconductor field effect transistor with a neck in the middle was measured at liquid‐nitrogen temperatures. The narrowest part of the gate with p+ isolations is 0.24 μm wide and about 0.2 μm long. The transconductance shows a peaked structure near the threshold voltage. The calculated transconductance based on the ballistic transport model of two‐dimensional electron gas explains well the peaked structure.

Oscillations at liquid‐nitrogen temperatures in the transconductance of a silicon metal‐oxide‐semiconductor field‐effect transistor with a neck in the middle

The conductance of a silicon metal‐oxide‐semiconductor field‐effect transistor, the gate of which has a neck in the middle, was measured at liquid‐helium temperatures and liquid‐nitrogen temperatures. The channel width in the neck region configured by SiO2 isolation regions is below 50 nm. The transconductance at liquid‐nitrogen temperatures shows periodic oscillations that are accentuated by negative substrate bias. We explain the results based on the one‐dimensional subbands formed in the neck region.