CBRAM is investigated as a NVM memory with respect to retention characteristics and multilevel capability. The CB-junction is characterised by photocurrent and photoluminescence. Measurement results showing the long-term data retention of the CBRAM technology are presented. The stability of four levels corresponds to the capability to store two bits. Scalability is shown with suitable switching characteristics and area-independent on-resistance down to sub 40 nm junction size. Operating conditions and circuits are introduced for CBRAM writing and voltage sensing.