| CPC H10N 70/063 (2023.02) [H10N 70/023 (2023.02); H10N 70/231 (2023.02); H10N 70/826 (2023.02)] | 20 Claims | 

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               1. A memory device, comprising: 
            a memory cell overlying an inter-metal dielectric (IMD) layer, the memory cell comprising a bottom electrode, a top electrode and a phase change element between the top electrode and the bottom electrode; 
                a protection coating on an outer sidewall of the phase change element, wherein the protection coating consists of a binary compound of carbon and hydrogen; and 
                a first sidewall spacer on an outer sidewall of the protection coating, the first sidewall spacer having a greater nitrogen atomic concentration than the protection coating, 
                wherein the protection coating forms a first interface with the phase change element, the first interface has a first slope at a first position and a second slope at a second position higher than the first position, the second slope is different from the first slope. 
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