Online information source for semiconductor professionals

ASM America, a subsidiary of ASM International, has developed an atomic layer deposition (ALD) process implementing lanthanum oxide (LaOx) and aluminum oxide (AlOx) high-k cap layers that enable 32nm generation high-k metal gate stacks using a single metal, instead of the two different metals first implemented with 45nm logic devices.

“Solving the integration challenges for high-k metal gates is a top priority for most of our customers,” explained Glen Wilk, Product Manager for transistor products at ASM. “This new process greatly simplifies the high-k metal gate integration and allows us to support gate first, as well as gate last process flows.  ASM now offers ALD processes for the high-k dielectric, cap layer, and metal gate.”

According to ASM, two different metals are needed to create the proper electrical characteristics of both sides (p and n) of the transistor switch, when not using a capping layer.  The use of an ultra-thin cap film between the hafnium-based gate dielectric and the metal gate, atomic level charges will affect the interaction between the dielectric and the metal.  

The proper metal film performance can be tuned by varying the cap film’s thickness in a range less than 1nm. ASM used its ‘Pulsar’ process module to deposit the films.