High-k Gate Oxide

Polysilicon (refractory) gate electrode 1975 Metal gate 2009-2011 Enable high-k gate oxides... 

It has been determined that Si02 needs to be replaced with a physically thicker layer of oxides of a higher dielectric constant (K) material, or high K gate oxides [1-8]. The maximum current density in interconnects between transistors resulted in the replacement of aluminum with copper as the conductor. The FET gate stack, which is the gate electrode and the dielectric layer between the gate and the silicon channel, is now the most serious problem. 

Robertson J, Xiong K, Falabretti B (2005) Point defects in Zr02 high K gate oxide. IEEE Trans Device Mater Rehab 5(1) 84. 

A serious potential problem related to the use of high-k gate dielectrics in SiC power MOSEETs can be encountered due to the much smaller (sometimes-negative) conduction band offsets between SiC and high-k metal oxides compared with silicon dioxide (see Table 5.1). Time-dependent dielectric breakdown (TDDB) and hot... 

Mabakal, A. et al., Inorganic oxide core, polymer shell nanocomposite as a high K gate dielectric for flexible electronics applications, J. Am. Chem. Soc. Ill (42), 14655-14662, 2005. 

The discussion of potential benefits and drawbacks of using high-k dielectrics as a gate oxide for power SiC UMOS transistors has been made in several publications [8, 10, 11]. A comparative analysis of different insulating materials suitable as gate... 

Figure 4.14. Cross-section high-resolution transmission electron microscopy (HRTEM) images of gate oxides for MOSFETs. Provided is an illustration of film thicknesses that result in identical capacitance for Si02( = 3.8), relative to a high- c dielectric k = 23.9) gate oxide. Hence, increased gate capacitance will result from thinner films comprising high- c dielectric materials. Reproduced with permission from Intel Corporation (http //www.intel.com).

Why is Ti02 used in dye-sensitized solar cells (DSCs) What other oxides would possibly be useful As discussed in this Chapter, next-generation CMOS ICs will employ high-K dielectric films as the gate insulator. A potential roadblock to this replacement is the possible incompatibility with current gate stacks - explain this problem, with possible solutions. 

Also, dielectric materials, especially, during the exposure to the atmosphere, absorb water and OH leads to detrimental interface reactions and water absorption and interface reactivity of yttrium oxide gate dielectrics on silicon was investigated. From the infrared absorption analysis, water vapor was significantly absorbed in the atmosphere. Similar oxidation are expected other high-K materials while the rate of OH absorption is expected to depend on the deposition process and their thermal history [29]. 

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