Browsing by Author "Lee, W. -C."

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In-Ga-O based double-heater phase change memory cell
(2008)
Wang, S. -L.
;
Chen, C. -Y.
;
Hsieh, M. -K.
;
Lee, W. -C.
;
Kung, A. H.
We report a new type of phase-change materials based upon the compound of In-Ga-O. It is found to exhibit two-order of magnitude resistivity change between the high-resistive amorphous phase and the low-resistive cubic phase at a phase-change temperature similar to 250 degrees C. When the In-Ga-O is incorporated into a nonvolatile phase change memory (PCM) device with a double-heater (DH) structure, it exhibits an on/off resistance ratio of 1000 and cycling over 300 times which are superior to those observed on a single-heater (SH) PCM device. These results, together with a low bias point of 70 mu A at 6.5 volt and 1.5mA at 3.5 volt, respectively, for set/ reset operation of the DH-PCM device to the crystalline/amorphous state, suggest that In-Ga-O is a promising material candidate for low power application of PCM devices.
Phase-change memory devices based on gallium-doped indium oxide
(2009-03-16)
Wang, S. -L.
;
Chen, C. -Y.
;
Hsieh, M. -K.
;
Lee, W. -C.
;
Kung, A. H.
We report repetitive phase-change memory (PCM) activity via the high- to low-resistance state transition in gallium-doped indium oxide (Ga:InO) induced by nanosecond electric pulses. The amorphous-to-crystalline phase transition of Ga:InO is found to occur at a crystallization temperature of similar to 250 degrees C with an activation energy of 1.27 +/- 0.07 eV. At the phase transition, we observe a change in two orders of magnitude in the PCM-device resistance, which can be correlated with the formation of (211) and {222} crystallites of bixbyite cubic In(2)O(3). We ascribe the phase-change mechanism to the Joule heating effect in Ga:InO.