Session 3A-5

pFET Vt control with HfO2/TiN/poly-Si gate stack
using a lateral oxygenation process

Abstract

In this contribution, it is demonstrated that the threshold voltage, Vt, of a pFET can be modulated with lateral oxygenation of the HfO2/TiN/poly-Si gate stack from the S/D sidewall after spacer removal. This process can be applied to MIPS (Metal-inserted poly-Si) gate stacks after high-T S/D activation without any additional interfacial layer (IL) growth. Using lateral oxygenation, the pFET Vt can be lowered by ~450 mV yielding a pFET with a Vt near band edge (within 250 mV). The shifted Vt is found to be stable during MOL/BEOL processing and the lateral oxygenation process does not degrade NBTI. Since Vt control is achieved with lateral oxygen diffusion, a channel length, L, dependence of Vt is observed. The Ldependence can be reduced by process optimization.