The drive uses the M.2 2280 form factor, which makes it 22 mm wide and 80 mm long.
While most other M.2 NVMe SSDs transfer data over the PCI-Express 3.0 x4 interface, the Samsung 980 Pro connects to the host system over a PCI-Express 4.0 x4 interface, which doubles the theoretical bandwidth.
On the PCB, you'll find the controller, two flash chips, and one DRAM chip; the other side of the PCB is empty.
Samsung has put a little copper foil on the back of the SSD it calls "a heat spreader label to deliver effective thermal control of the NAND chip." Yeah, not really, I doubt it makes any significant difference. It certainly doesn't have much thermal capacity simply because it has so little mass. Also, the hottest component of the drive is the controller chip, not the flash, so the label isn't positioned correctly.
Chip Component Analysis
This is Samsung's new PCIe Gen 4 controller called "Elpis." It is produced on a 8 nm production process in Samsung's foundries, same as NVIDIA's Ampere GPUs. Compared to previous controllers, Elpis can process 128 queues at the same time (Phoenix had 32, UBX only 8).
The two flash chips are Samsung TLC V-NAND v6, which has between 110 and 136 layers. Each chip has a capacity of 512 GB.
A Samsung LPDDR4 chip provides 1 GB of fast DRAM storage for the controller to store the mapping tables.