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We designed the phase-change memory (PCM) cell based on ultrathin GeTe film (∼10 nm) and homemade nanoscale electrode filling craft to improve data retention ability and reduce programming energy, respectively. It was found that the temperature for ten years’ data retention of this ultrathin GeTe film is 160 ± 32.8 °C, which is much higher than that of conventional Ge2Sb2Te5 (GST, 83 ± 20.6 °C) film. Benefit to the nature of fragile-to-strong crossover behavior in GeTe supercooled liquids that was confined in a two-dimension structure, a fast SET speed of 6 ns is also detected in this ultrathin GeTe PCM. Moreover, the RESET power consumption of this ultrathin GeTe PCM is measured as 1.8 ± 0.5 nJ, and it is much lower than that of GST PCM (16.5 ± 1.5 nJ), which is attributed to the nanoscale electrode of the devices. The above-mentioned improvements enable the application of ultrathin GeTe PCM in neuromorphic computing.

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Gas doping is an effective way for enhancing thermal stability significantly for phase-change materials, but the negative effects are not studied extensively. In this work, we investigated the influences of different oxygen-doping concentrations on the crystallization kinetics of Sb-GeO2 (SGO) films. The nanocomposite SGO film, which consists of strong GeO2 and a fragile Sb matrix, exhibits a distinct fragile-to-strong crossover (FSC) behavior. It implies that there is a potential ability to balance the crystallization speed and thermal stability in the SGO material. Nevertheless, such FSC behavior becomes weak with the introduction of additional oxygen, and it totally vanishes after more oxygen introduction. It was confirmed that the fade of FSC behavior in additional O2-doped SGO films is closely related to the formation and separation of the Sb2O3 phase in amorphous and crystalline structures, respectively. The introduction of a large amount of oxygen improves the thermal stability of the SGO film, but the crystal growth rate decreases obviously. The maximum crystal growth rate (U max) is 2.3 m s–1 for the SGO film, and the U max of SGO with additional O2 of 15 and 17% (O2/Ar ratio) is 1.2 and 0.6 m s–1, respectively. The quantitative analysis on kinetic features provides us an opportunity to study both the advantages and disadvantages of oxygen introduction into the phase-change matrix.