Channel/ferroelectric interface modification in ZnO non-volatile memory TFT with P(VDF-TrFE) polymer

We report on the fabrication of ZnO non-volatile memory thin-film transistors (NVM-TFTs) with 200 nm-thick poly(vinylidene fluoride/ trifluoroethylene)[P(VDF-TrFE)] ferroelectric layer. The NVM-TFTs have been tested for the most optimum properties in respect of their memory windows and memory retention properties, as prepared with the modified channel/ferroelectric interfaces inserted by respective thin buffer layers: 1, 3, 5, 10, and 20 nm-thin Al₂O₃, or 1 nm-thin inorganic-organic hybrid dielectrics of a AlO_x-(or TiO_x-) self assembled monolayer (SAM). All our NVM-TFTs operated on glass substrates under the low-voltage WR-ER pulses of ±20 V with a maximum field effect mobility of ∼1 cm ²/V s and memory window of 12∼16 V. Among all the NVM-TFTs, the device with the 5 nm-thin Al₂O₃ buffer demonstrated the longest retention time of more than 10⁴ s without much reduction of write-to-erase (WR/ER) current ratio, keeping a good memory window of ∼16 V and WR/ER ratio of ∼40.