High k metal gate technology pdf

Sram with hkmg process has yielded, complements foundrys 3228nm technology hsinchu, taiwan, nov. With these and allied technologies the industry was able. Conference paper pdf available in digest of technical papers symposium on vlsi technology july. The trigate transistor architecture introduces the fewest changes to conventional planar transistor processing. Over years was the material of choice as gate insulator. However, the use of high k metal gate require a ntype metal and a ptype. Intel made a significant breakthrough in the 45nm process by using a high k hi k material called hafnium to replace the transistors silicon dioxide gate dielectric, and by using new metals to replace the n and pmos polysilicon gate electrodes. We show that the performance of hkmg transistors has a strong dependency on the. Challenges in spacer process development for leading.

The past, present and future of highkmetal gates citeseerx. Like other technology components of the semiconductor industry, the highk metal gate has also continued innovation since its introduction to the 45 nm node. Unacceptably high levels of bti degradation in both nmos and pmos are observed on hk with. High k gate dielectrics for future cmos technology t. They showed a working sram array with good process yield, performance, and reliability. Highkmetal gate article about highkmetal gate by the. Why is a metal used instead of polysilicon for highk gate. Highmetal gate technology is on the verge of replacing conventional oxynitride dielectrics in stateoftheart transistors for both highperformance and lowpower applications. Recent trend from topdown lithography to selfalignment and bottomup patterning approaches source. Both provide twice the gate density of comparable 40nm processes and an sram cell size shrink. The replacement metal gate rmg height range and defectivity fall on particle, al residue, corrosion and microscratch performance controls are very challenging for highk metal gate hkmg rmg chemical mechanical polishing cmp processes.

Intel made a significant breakthrough in the 45nm process by using a highk hik material called hafnium to replace the transistors silicon dioxide gate dielectric, and by using new metals to replace the n and pmos polysilicon gate electrodes. Highk, quantum mechanical tunneling and gate leakage. Dualepitaxy and multiple stressors are essential to boost the device performance. Comparison of 32nm highk metal gate predictive technology model cmos and mosfetlike cnfet compact model based domino logic circuits saravana maruthamuthu, wireless group. Challenges in spacer process development for leadingedge highk metal gate technology. Gate leakage current, polysilicon gate depletion, boron penetration. There is certainly a benefit to moving from 40nm to 28nm.

From the 45 nm node onward, the metal gate technology returns, together with the use of highdielectric materials, pioneered by intel developments. Like other technology components of the semiconductor industry, the highkmetal gate has also continued innovation since its introduction to the 45 nm node. With the exception of the highk dielectric, the first part of the process is similar to older technology nodes and includes shallow trench isolation, channel implants for threshold voltage, atomic layer deposition for the highk gate dielectric, and a polysilicon gate conductor layer. Gang he is professor at the school of physics and materials science of the anhui university, china. The metal gate for nmos transistors requires a work. Chau and colleagues explained the problem that led to the use of a metal gate in detail in highkmetalgate stack and its mosfet characteristics, ieee electron. Highk gate dielectrics for future cmos technology t. Once youve replace the sio2 gate oxide with highk dielectrics hafnium oxide or zirconium oxide you band diagram is completely different. Highk\metalgate stack achieves nmos and pmos channel mobility close to sio2s. Pdf highkmetal gates in leading edge silicon devices. Work functions for nmos and pmos breakthroughs with metal gates ntype metal and ptype metal with the correct work functions on highk have been engineered. Intels highkmetal gate technology enabled elements on a chip to be reduced to 45 nm with stability.

Enabling metal depostition technology for highk metal. Metal gate high k dielectric stack metal gate elect rodes may be more effective than polysi in screening the high k so phonons from coupling to the channel under inversion conditions, resulting in improved channel mobility 78. Pdf highkmetal gate stacks in gate first and replacement gate. View the slideshow or click on each individual thumbnail. In this study, a robust aluminum metal cmp alcmp process development was investigated to meet the criteria of rmg at 28. Osburn north carolina state university, raleigh, nc 27695 introduction high k gate dielectrics and metal gates are being widely studied for next generation devices,s dry etched and all the other zro. Metaldielectric band alignment and its implications for metal gate complementary metaloxidesemiconductor technology yeechia yeo,a tsujae king, and chenming hu department of electrical engineering and computer sciences, university of california. Ma yale university, center for microelectronics, and department of electrical engineering new haven, ct 065208284 introduction high k dielectrics are being actively pursued by the semiconductor industry to replace sio2 as the gate dielectric for future generations of cmos transistors. We discuss challenges in manufacturing finfet beyond those typical ones discussed in cost. Highk materials and metal gates for cmos applications. Process development of highk metal gate aluminum cmp at. Intel corporations announcement of a replacement gate build strategy for highk metal gate technology in their 45 nm device node has inspireddesigns for the sub. The incorporation of highk dielectrics with metal gates into a manufacturable, high volume transistor process is the result of tremendous ingenuity and effort by many scientists and engineers. When the gate is pulsed, current flows between the source and drain.

His research interests and efforts cover the areas of the preparation, characterization, fundamental understanding and associated applications of high. Our 28nm platform is based on industry mainstream technology that includes conventional polyoxynitride process and gate last, highk metal gate, which provides superior performance over gate first highk offerings. Highk metal gate hkmg technology has become one of the frontrunners for the next generation of cmos devices. Sixteen new intel chips incorporate 45nm hafniumbased highk metal gate transistors. Chau and colleagues explained the problem that led to the use of a metal gate in detail in high k metal gate stack and its mosfet characteristics, ieee electron. Tsmcs industryleading 28nm process technology mainly uses highk metal gate hkmg gatelast technology. However, different schemes to integrate those novel materials have been recently proposed, traditionally referred to as gate first and gate last. Metaldielectric band alignment and its implications for. Cmp solutions for the integration of high k metal gate. Highkmetal gate technology represents a fundamental and their effect reduce with geometrical scaling ofthe chip. This marked the return of metal gate technology on silicon for the first time since polysilicon gates.

Pdf challenges in spacer process development for leading. He obtained his academic degrees from the institute of solid state physics of the chinese academy of sciences. Highk\metalgate stack shows significantly lower gate leakage than sio2. In addition to the pmos nbti, nmos pbti degradation has been observed 1. Challenges in manufacturing finfet at 20nm node and beyond minhwa chi technology development, globalfoundries, malta, ny 12020, usa. Challenges in spacer process development for leadingedge high k metal gate technology. The incorporation of high k dielectrics with metal gates into a manufacturable, high volume transistor process is the result of tremendous ingenuity and effort by many scientists and engineers. Ma yale university, center for microelectronics, and department of electrical engineering new haven, ct 065208284 introduction highk dielectrics are being actively pursued by the semiconductor industry to replace sio2 as the gate dielectric for future generations of cmos transistors. Direct tunneling leakage current start to flow when the thickness is 3 nm.

The evolution of highk metal gate transistors, from the first planar 45nm to the latest 14nm node. Advanced metal gatehighk dielectric stacks for high. The finfet on bulk has good process compatibility to. As elements in the chip were being reduced to 45 nanometers, the gate dielectric began to lose its insulating dielectric quality and exhibited too much leakage. The solution was to replace the transistors silicon dioxide gate. Pdf in this work, representative highkmetal gate moscapacitor stacks. Transistor performance has been boosted by other means. The availability of highkmetal gate technology offers quite a few advantages in terms of power reduction.

Ald highk as a common gate stack solution for nano. Eot scaling and reliability concerns when hfbased highk ultrathin gate oxides are integrated into high temperature cmos processes. Doan of micron technology initiated the development of atomic layer deposition highk films for. This new technology incorporates a highk dielectric, which reduces leakage and improves the dielectric constant.

A systematic consideration of the required properties of gate dielectrics indicates that the key guidelines for selecting an alternative gate dielectric are a. Compared to the gatefirst technology, the gatelast offering provides more advantages, including lower leakage current and better chip performance. Highk gate dielectric national university of singapore. In this work the combination of ultra thin highk gate dielectric, near midgap metal gate workfunction, low doping in the channel and optimized fin dimensions enable us to fully enhance.