According to Moore9s law, the number of transistors on a chip should double in each technology generation. For more than 30 years, compliance with this law has been driven by the shrinking of transistor dimensions. But as
Lundstrom
explains in his Perspective, device physics and the limitations of existing materials pose restrictions on how far transistor dimensions can be reduced. Moore9s law may nevertheless survive as device engineers build layers of devices on chips or use new approaches such as molecular electronics.