K. C. Chiang

Very high-density (23 fF//spl mu/m/sup 2/) RF MIM capacitors using high-/spl kappa/ TaTiO as the dielectric

A very high density of 23 fF//spl mu/m/sup 2/ has been measured in RF metal-insulator-metal (MIM) capacitors which use high-/spl kappa/ TaTiO as the dielectric. In addition, the devices show a small reduction of 1.8% in the capacitance, from 100 kHz to 10 GHz. Together with these characteristics the MIM capacitors show low leakage currents and a small voltage-dependence of capacitance at 1 GHz. These TaTiO MIM capacitors should be useful for precision RF circuits.

High-Temperature Leakage Improvement in Metal–Insulator–Metal Capacitors by Work–Function Tuning

Using low-cost and high work-function Ni, a low leakage current of 5times10-6 A/cm2 at 125 degC is obtained in a high 25-fF/mum2-density SrTiO3 metal-insulator-metal (MIM) capacitor processed at 400 degC. This is approximately two orders of magnitude better than the same device using a TaN electrode, with added advantages of improved voltage and temperature coefficients of capacitance. This work-function tuning method also has merit for achieving both low thermal leakage and high overall kappa value beyond previous laminate structure

Fully silicided NiSi:Hf-LaAlO/sub 3//SG-GOI n-MOSFETs with high electron mobility

We have integrated the low work function NiSi:Hf gate on high-/spl kappa/ LaAlO/sub 3/ and on smart-cut Ge-on-insulator (SC-GOI) n-MOSFETs. At 1.4-nm equivalent oxide thickness, the NiSi:Hf-LaAlO/sub 3//SC-GOI n-MOSFET has comparable gate leakage current with the control Al gate on LaAlO/sub 3/-Si MOSFETs that is /spl sim/5 orders of magnitude lower than SiO/sub 2/. In addition, the LaAlO/sub 3//SC-GOI n-MOSFET with a metal-like fully NiSi:Hf gate has high peak electron mobility of 398 cm/sup 2//Vs and 1.7 times higher than LaAlO/sub 3/-Si devices.

High-performance poly-silicon TFTs incorporating LaAlO/sub 3/ as the gate dielectric

We have integrated a high-/spl kappa/ LaAlO/sub 3/ dielectric into low-temperature poly-Si (LTPS) thin-film transistors (TFTs). Good TFT performance was achieved-such as a high drive current, low threshold voltage and subthreshold slope, as well as an excellent on/off current ratio and high gate-dielectric breakdown field. This was achieved without hydrogen passivation or special crystallization steps. The good performance is related to the high gate capacitance density and small equivalent-oxide thickness provided by the high-/spl kappa/ dielectric.

High-/spl kappa/ Ir/TiTaO/TaN capacitors suitable for analog IC applications

We have developed novel high-/spl kappa/ Ir/TiTaO/TaN capacitors which have high-capacitance density (10.3 fF//spl mu/m/sup 2/), small leakage current at 2 V (1.2/spl times/10/sup -8/ A/cm/sup 2/), and low voltage linearity of the capacitance (89 ppm/V/sup 2/). These excellent results meet the ITRS roadmap requirements for precision analog capacitors for the year 2018. The good performance is due to the very high /spl kappa/ (45) achieved in the TiTaO dielectric and the high work-function (5.2 eV) provided by the Ir electrode.

Use of a High-Work-Function Ni Electrode to Improve the Stress Reliability of Analog

We have studied the stress reliability of low-energy-bandgap high- metal-insulator-metal capacitors under constant voltage stress. By using a high-work-function Ni electrode (5.1 eV), we reduced the degrading effects of stress on the capacitance variation (DeltaC/C), the quadratic voltage coefficient of capacitance (VCC-alpha), and the long-term reliability, in contrast with using a TaN. The improved stress reliability for the Ni electrode capacitors is attributed to a reduction of carrier injection and trapping.

\hbox{SrTiO}_{3}

For the first time, high density (10.3 fF//spl mu/m/sup 2/), low voltage linearity (/spl alpha/=89 ppm/V/sup 2/) and small leakage current (1.2/spl times/10/sup -82/ A/cm/sup 2/ or 5.8 fA/[pF/spl middot/V] at 2V) meet all the ITRS requirements of analog capacitor at year 2018. These are achieved by novel high-K TiTaO (K=45) and high work-function Ir capacitor, which further improve to very high 23 fF//spl mu/m/sup 2/ density and low 81 ppm/V/sup 2/ linearity for higher speed analog/RF ICs at 1GHz, using the fast /spl alpha/ decay mechanism with increasing frequency.

Metal–Insulator–Metal Capacitors

We have fabricated high-kappa Ni/TiO₂/ZrO₂/TiN metal-insulator-metal (MIM) capacitors. A low leakage current of 8 times 10^-8 A/cm² at 125degC was obtained with a high 38- fF/mum² capacitance density and better than the ZrO₂ MIM capacitors. The excellent device performance is due to the lower electric field in 9.5-nm-thick TiO₂/ZrO₂ devices to decrease the leakage current and to a higher kappa value of 58 for TiO₂ as compared with that of ZrO₂ to preserve the high capacitance density.

Very high K and high density TiTaO MIM capacitors for analog and RF applications

An unavoidable drawback when using high-K dielectrics in capacitors is the small bandgap and the related reduction in the band-offset, which results in a large leakage current at elevated temperatures. We report improvements in the thermal leakage current by using Ni as a high-work-function top electrode for high-K TiHfO capacitors. This avoids sacrificing the overall K value by using a multilayer or laminate structure and results in better voltage linearity, which is important for analog/radio frequency integrated circuits.

High-Density and Low-Leakage-Current MIM Capacitor Using Stacked

A novel microstrip line layout is developed to directly measure the minimum noise figure (NF/sub min/) accurately instead of the complicated de-embedding procedure in the conventional CPW line. A very low NF/sub min/ of 1.05 dB at 10 GHz is directly measured in 16 gate finger 0.18 /spl mu/m MOSFETs without any de-embedding. Based on the accurate NF/sub min/ measurement, we have developed a self-consistent DC, S-parameters, and NF/sub min/ model to predict device characteristics after the continuous stress, with good accuracy.