The present disclosure provides a Non-Volatile Memory (NVM) cell and programming method thereof. The cell can denote at least two logic levels. The cell has a read-transistor with a floating gate, and Band-To-Band-Tunneling device (BTBT device) sharing the floating gate with the read-transistor. The BTBT device is configured as an injection device for injecting a first charge onto the floating gate when the BTBT device is biased with a first gate bias voltage such that the BTBT device is in accumulation, to set at least one of the logic levels. A first electrode is coupled to bias the BTBT device with a first bias voltage that is higher than the first threshold voltage. The first bias voltage is controlled such that the BTBT device is in accumulation during a write operation. The injected amount of charge on the floating gate is determined by the first bias voltage.