Paper AS-WeA9
Advantages of AR-Hard X-ray Photoelectron Spectroscopy (HAXPES) in the Characterization of Advanced Semiconductor films.

Wednesday, November 11, 2009, 4:40 pm, Room C2

High-dielectric constant materials such as HfO2 and metal gates such as TiN are promising materials for the fabrication of high speed, low power consumption devices.

In these systems, the control of the interfaces between the dielectric materials and the electrodes is crucial. Effects such as intermixing, chemical reactions, formation of crystalline domains, etc. require detailed investigation, especially in the new metal gate materials replacing the poly-silicon electrode. Angle –resolved soft X-ray XPS is often employed to probe chemical and structural changes of the individual dielectric and metal layer. Material intermixing, oxygen vacancies and molecular structure at the interfaces play a fundamental role in predicting the electrical performance of the final devices. Probing the entire film stack without any manipulation ( spattering, FIB, etc.) is a big challenge for all the metrology presently available in the industrial analytical laboratories. Collaborations between industry and universities may greatly help in developing these advanced devices.

In this work we present the “non destructive” characterization of the total film stack by Hard X-ray AR-XPS ( X-ray energy~ 6000eV). This film, under development for 32nm node technology, consists of 50A poly-Si and 100A TiN as a metal gate, of 20A HfO2 as a high dielectric constant material, of a 10A SiO2 on Si substrate.

. This paper will report recent results on chemical and structural information obtained at the TiN/HfO2 interface. Intermixing of TiN and HfO have been observed by TEM analysis, but for the first time we can show that the Hf4f is sensitive to its environments and shows a multiple peak structure probably due to Hf bonded to O and to N.