Superlattice-like Ga40Sb60/Sb films with ultra-high speed and low power for phase change memory application

Abstract

Superlattice-like (SLL) Ga40Sb60/Sb (GSS) is proposed for its ultra-high speed, low power for phase change application. The excellent properties derives from the properly designed SLL structure of Sb layers with high speed and low crystallization temperature (Tc) inserting high Tc Ga40Sb60. Appropriate Tc ~ 220 °C and ultra-long data retention (151 °C for 10 years) is obtained in the SLL [Ga40Sb60(5 nm)/Sb(4 nm)]5 thin films. X-ray diffraction analysis shows that only Sb phase exists in the SLL GSS thin films and the low surface roughness is confirmed by AFM measurement. Moreover, the phase change memory devices based on Ge2Sb2Te5 (GST) and SLL [Ga40Sb60(5 nm)/Sb(4 nm)]5 thin films were fabricated and the set and reset operation was studied. The current–voltage measurement for set operations shows the threshold switching voltage (2.0 V) is smaller than the GST (4.4 V). The resistance–voltage tests indicate the reversible phase change could be realized by a pulse as short as 10 ns and the reset power of the [Ga40Sb60(5 nm)/Sb(4 nm)]5 cell calculated as 2.3 × 10−11 J is 6.5 times lower than the GST cell 1.5 × 10−10 J.