Effect of Ion Implantation and Anneals on Fully-strained SiC and SiC:P Films using Multiple Characterization Techniques

Autor: R. Takalkar, Anita Madan, Dominic J. Schepis, Eric C. Harley, Bin Yang, Abhishek Dube, Teresa L. Pinto, Zhibin Ren, Thomas N. Adam, Linda Black, Z. Zhu, Johan W. Weijtmans, Rainer Loesing, Jinghong Li, Ashima B. Chakravarti
Rok vydání: 2008
Předmět:
Zdroj: ECS Transactions. 16:325-332
ISSN: 1938-6737
1938-5862
Popis: In addition to device scaling, strain engineering using SiC stressors in the S/D regions is important for nFET performance enhancement [1-3]. In this paper, we review the characterization of fully-strained epitaxial SiC and in-situ doped SiC:P films for various ion implant conditions and anneals that are typically used in traditional CMOS flows. μXRD strain measurements and SIMS (C and P content) were performed on reference test macros on patterned lithographic wafers. μXRD strain measurements (related to substitutional C) of the asdeposited SiC films show that the C is lower than the actual C suggesting that there is interstitial C in the film. After M1 device measurements, Nanobeam Diffraction (NBD) analysis to determine channel strain was done on selected samples. An in-line μXRD system was used to monitor the strain and thickness variation of the SiC stressor with critical processing steps. Typical uXRD measurements demonstrate that there is a depth profile for the crystalline integrity of the SiC stressor films. The top surface which is in the implant range shows no strain (amorphization due to implants) compared to the fully strained, deeper regions (Fig 1). Figure 2 shows a typical cross-sectional TEM image and NBD patterns with the as-deposited SiC embedded in the source and drain. After M1 device measurements, good correlation was seen between the NBD and uXRD measurements (Fig 3). Stressor strain for samples 1-4 was retained after complete processing. Sample 5 which saw a high temperature anneal showed a complete loss of strain. This correlated well with the device results [4]. Full characterization has helped identify process integration schemes which give significant drive current enhancements [4].
Databáze: OpenAIRE
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