Fang-g Chen

25 nm CMOS Omega FETs

Low leakage and low active-power 25 nm gate length C-MOSFETs are demonstrated for the first time with a newly proposed Omega-(/spl Omega/) shaped structure, at a conservative 17-19 /spl Aring/ gate oxide thickness, and with excellent hot carrier immunity. For 1 volt operation, the transistors give drive currents of 1440 /spl mu/A//spl mu/m and 780 /spl mu/A//spl mu/m with off state leakage currents of 8 nA//spl mu/m and 0.4 nA//spl mu/m for N-FET and P-FET, respectively. A low voltage version achieves, at 0.7 V, drive currents of 1300 /spl mu/A//spl mu/m for N-FET and 550 /spl mu/A//spl mu/m for P-FET at an off current of 1 /spl mu/A//spl mu/m. N-FET gate delay (CV/I) of 0.39 ps and P-FET gate delay of 0.88 ps exceed International Technology Roadmap for Semiconductors (ITRS) projections.

35 nm CMOS FinFETs

We demonstrate for the first time high performance 35 nm CMOS FinFETs. Symmetrical NFET and PFET off-state leakage is realized with a simple technology. For 1 volt operation at a conservative 24 /spl Aring/ gate oxide thickness, the transistors give drive currents of 1240 /spl mu/A//spl mu/m for NFET and 500 /spl mu/A//spl mu/m for PFET at an off current of 200 nA//spl mu/m. Excellent hot carrier immunity is achieved. Device performance parameters exceed ITRS projections.

Application of optical CD metrology based on both spectroscopic ellipsometry and scatterometry for Si-recess monitor

Scatterometry is gaining popularity in recent years as it shows itself as a worthy contender among existing metrology systems. Scatterometry provides fast, accurate and precise profile information, which is valuable for in-line process control in production environment. Scatterometry applications widely adopted in IC fabs include poly gate ADI and AEI, and shallow trench isolation depth measurements. Recently, the mobility enhancement by compressive strain at source/drain is reported which improves greatly PMOS Idsat. In this work, we extend the application domain of scatterometry technology to two-dimensional recessed Si profile used in strained source and drain (SSD) structures. Complexity of SSD structures measurement by scatterometry requires the use of many parameters in modeling, which hinders a stable library setup. Our approach in circumventing this issue is to identify the most sensitive parameters first and then further reduce the number of variables through an effective medium approximation (EMA). This paper will discuss the preparation, experiments, and results of the scatterometry measurements. The extracted data have been compared with transmission electron microscopy results. Good correlation in depth and profile are observed. In addition, we have performed repeatability test and fault detection checks and the trend chart indicates that our methodology is very robust for in-line process monitor.

Application of spectroscopic ellipsometry-based scatterometry for ultrathin spacer structure

The scatterometry technology has been developed widely in the poly gate and resist patterning application for critical dimension (CD) process control. The advantages of this technology are good precision, short cycle time and multiple information outputs. To extend this application even further on spectroscopic ellipsometry (SE) based scatterometry, the spacer structure application becomes one promising goal. In this work, we use SE based scatterometry to demonstrate a two-dimensional profile of ultra thin spacer with post-etched structure as well as CD measurement of the spacer. A brief theory and measurement results taken by dense and isolate structure will be discussed in this paper. The cross-section of TEM and the spectra fitting by scatterometry are also collected at the same location and compared. It shows a high correlation between the two. Finally, an example of minispacer fault detection methodology and repeatability test on scatterometry is also presented to show the capability for volume production.