Prior art

To identify the most relevant prior art for US patent 8253180, I need to access its citations within the USPTO database. Since I cannot directly interact with a live USPTO database in the way a human analyst would, I will rely on the list of "Prior art keywords" and "Prior art date" provided in the patent text itself, as well as the explicitly cited academic/technical papers in the "BACKGROUND OF THE INVENTION" and "DESCRIPTION OF THE PREFERRED EMBODIMENTS" sections. These explicitly mentioned references are considered highly relevant by the patent examiner and the inventors.

The Google Patents page for US8253180B2 also provides a list of "Prior art references" under the "Citations" section (which I cannot directly view through this interface, but the description text itself provides some key ones).

Based on the provided patent text, the following prior art references are explicitly discussed and cited by the inventors:

1. "HfSiON - CMOS technology for achieving high performance and high reliability" (Watanabe, 2005)

• Full Citation: Ken Watanabe, "HfSiON - CMOS technology for achieving high performance and high reliability," Semi. Forum Japan, 2005. [cite: The full patent text, "FIGS. 16A and 16B are cross-sectional views illustrating respective structures of known MISFETs using a high dielectric constant gate insulating film, respectively (see Ken Watanabe, HfSiON - CMOS technology for achieving high performance and high reliability, Semi. Forum Japan, 2005)."]
• Publication/Filing Date: 2005 (as per the citation).
• Brief Description: This reference illustrates structures of known MISFETs utilizing a high dielectric constant gate insulating film. Specifically, FIG. 16A depicts a MISFET with a gate electrode on a high dielectric constant gate insulating film, and an insulating sidewall on each side. FIG. 16B shows a similar structure but includes an insulating offset sidewall between the gate electrode and the main sidewall to optimize the gate-extension overlap. [cite: The full patent text, "As shown in FIG. 16A , a gate electrode 105 is formed on a region of a well 102 surrounded by a STI (shallow trench isolation) 103 . The gate electrode 105 is provided on the region with a high dielectric constant gate insulating film 104 interposed therebetween. An insulating sidewall 107 is formed on each side of the gate electrode 105 .", "A structure shown in FIG. 16B is different from a structure shown in FIG. 16A in that a sidewall 107 is formed on each side of a gate electrode 105 with an insulating offset sidewall 106 interposed therebetween."]
• Potentially Anticipates (35 U.S.C. § 102): While not directly anticipating the novel features of US8253180, Watanabe teaches the core components and basic configurations of MISFETs with high-k gate dielectrics and sidewalls. Specifically, it discloses:
  • A high dielectric constant gate insulating film on an active region of a substrate.
  • A gate electrode formed on the high dielectric constant gate insulating film.
  • An insulating sidewall formed on each side surface of the gate electrode (FIG. 16A).
  • An insulating offset sidewall in addition to a main sidewall (FIG. 16B).
    Therefore, it anticipates the fundamental structural elements present in claims like Claim 1 and Claim 13, but not the specific improvement of the continuous, thinned high-k film under the sidewall. It serves as foundational prior art for the environment in which the invention operates.

2. "IEDM Tech. Dig., 1989, p. 777" (Hori, 1989)

• Full Citation: T. Hori, "IEDM Tech. Dig., 1989, p. 777." [cite: The full patent text, "As a result, a high overlapping effect between a gate and a drain can be achieved (see T. Hori, IEDM Tech. Dig., 1989, p. 777)."]
• Publication/Filing Date: 1989 (as per the citation).
• Brief Description: This reference is cited in US8253180 for the concept of achieving a "high overlapping effect between a gate and a drain." [cite: The full patent text, "As a result, a high overlapping effect between a gate and a drain can be achieved (see T. Hori, IEDM Tech. Dig., 1989, p. 777)."] This effect is stated to improve device characteristics and hot carrier reliability.
• Potentially Anticipates (35 U.S.C. § 102): Hori appears to anticipate the concept of optimizing gate-drain overlap for device performance and reliability. However, it does not describe the specific structural solution (continuous, thinned high-k film under the sidewall) disclosed in US8253180 for achieving this effect in the context of high-k gate insulating films. It relates more to the desired outcome or problem addressed by US8253180.

3. "IEDM Tech. Dig., 2000, p. 239" (Sayama et al., 2000)

• Full Citation: H. Sayama et al., "IEDM Tech. Dig., 2000, p. 239." [cite: The full patent text, "a double sidewall type MISFET (see H. Sayama et al., IEDM Tech. Dig., 2000, p. 239) in which an overlapping amount between a gate electrode and an extension region can be optimized in a simple manner will be described in the second embodiment."]
• Publication/Filing Date: 2000 (as per the citation).
• Brief Description: This reference describes a "double sidewall type MISFET in which an overlapping amount between a gate electrode and an extension region can be optimized in a simple manner." [cite: The full patent text, "a double sidewall type MISFET (see H. Sayama et al., IEDM Tech. Dig., 2000, p. 239) in which an overlapping amount between a gate electrode and an extension region can be optimized in a simple manner will be described in the second embodiment."] This is specifically mentioned in relation to the second and third embodiments of US8253180, which also feature double sidewall structures.
• Potentially Anticipates (35 U.S.C. § 102): Sayama et al. directly anticipates the use of a "double sidewall type MISFET" structure and the motivation to use it for optimizing the overlap between a gate electrode and an extension region. This directly relates to the structural basis of claims such as Independent Claims 13, 14, 15, 16, and 17, which describe devices with a first and second insulating sidewall. However, it does not explicitly disclose the unique continuous and thinned high-k gate insulating film under these sidewalls as claimed in US8253180.