There are quite a few manufacturers that are producing different BIOS chips: Award, AMI, Phoenix, and IBM. Most commonly you can find AMIs, AWARDs and PHOENIXes. The BIOS is stored on a ROM chip.
These ROM BIOS chips can be of different measurements and look different from each other. Check out the following two types of chips. The one on the left is an AWARD (as stated on the sticker), while the one on the right is a Phoenix chip.