A mmWave Phase Shifter Based on Ferroelectric Hafnium Zirconium Oxide Varactors

Abdulazhanov, Sukhrob; Le, Quang Huy; Huynh, Dang Khoa; Wang, Defu; Gerlach, Gerald; Kampf, Thomas

doi:10.1109/imws-amp.2019.8880144

Cited by 15 publications

(14 citation statements)

References 14 publications

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“…Fig. 2c shows how the model correctly converges to the expected voltage reported in the literature [6,9] without any a priori assumption, [6,9]. The extracted values are lower than those reported for purely orthorhombic HZO due to .…”

Section: Proposed Small-signal Model Of the Ftjsupporting

confidence: 58%

“…) as in Fig. 2b, where and are the permittivity of the orthorhombic (i.e., taken to be around 36 [6]) and non-orthorhombic phases, respectively, and is the fraction of the area occupied by orthorhombic grains, a parameter that is then estimated by reproducing experimental data. These values are considered for simplicity to be frequency-independent, as it was shown up to a few GHz using dedicated test structures [8].…”

Section: Proposed Small-signal Model Of the Ftjmentioning

confidence: 99%

“…These values are considered for simplicity to be frequency-independent, as it was shown up to a few GHz using dedicated test structures [8]. The voltage dependence [6,9] is also considered. Fig.…”

Section: Proposed Small-signal Model Of the Ftjmentioning

confidence: 99%

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Understanding the Reliability of Ferroelectric Tunnel Junction Operations using an Advanced Small-Signal Model

Benatti

Puglisi

2021

2021 IEEE International Integrated Reliability Workshop (IIRW)

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Ferroelectric technology is becoming ever more appealing for a variety of applications, especially analog neuromorphic computing. In this respect, elucidating the physical mechanisms occurring during device operation is of key importance to improve the reliability of ferroelectric devices. In this work, we investigate ferroelectric tunnel junctions (FTJs) consisting of a ferroelectric hafnium zirconium oxide (HZO) layer and an alumina (Al2O3) layer by means of C-f and G-f measurements performed at multiple voltages and temperatures. For a dependable interpretation of the results, a new small signal model is introduced that goes beyond the state of the art by i) separating the role of the leakage in the two layers; ii) including the significant impact of the series impedance (that depends on the samples layout); iii) including the frequency dependence of the dielectric permittivity; iv) accounting for the fact that likely not the whole HZO volume crystallizes in the orthorhombic ferroelectric phase. The model correctly reproduces measurements taken on different devices in different conditions. Results highlight that the typical estimation method for interface trap density may be misleading.

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Section: Proposed Small-signal Model Of the Ftjsupporting

confidence: 58%

Section: Proposed Small-signal Model Of the Ftjmentioning

confidence: 99%

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Understanding the Reliability of Ferroelectric Tunnel Junction Operations using an Advanced Small-Signal Model

Benatti

Puglisi

2021

2021 IEEE International Integrated Reliability Workshop (IIRW)

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“…Here an increase of permittivity appears with electric field cycling for Hf-rich samples, due to the crystallization into the ferroelectric phase, whereas only minor changes are observed for the crystalline Zr-rich films, due to the reorientation of the polarization axis. This behavior is very interesting for the implementation of HZO as a ferroelectric thin film varactor [19][20][21] . The Hf-rich samples show a high capacitance tunability, as demonstrated in Fig.…”

mentioning

confidence: 91%

Electric field-induced crystallization of ferroelectric hafnium zirconium oxide

Lederer

Abdulazhanov

Olivo

et al. 2021

Sci Rep

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Ferroelectricity in crystalline hafnium oxide thin films is strongly investigated for the application in non-volatile memories, sensors and other applications. Especially for back-end-of-line (BEoL) integration the decrease of crystallization temperature is of major importance. However, an alternative method for inducing ferroelectricity in amorphous or semi-crystalline hafnium zirconium oxide films is presented here, using the newly discovered effect of electric field-induced crystallization in hafnium oxide films. When applying this method, an outstanding remanent polarization value of 2P$$_{\mathrm{R}}$$ R = 47 $$\upmu$$ μ C/cm$$^{2}$$ 2 is achieved for a 5 nm thin film. Besides the influence of Zr content on the film crystallinity, the reliability of films crystallized with this effect is explored, highlighting the controlled crystallization, excellent endurance and long-term retention.

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“…Varactors, based on ferroelectric HZO interdigitated capacitors were first proposed by Dragoman group [12][13][14][15][16]. We have also proposed the use of CMOS compatible devices in the BEoL, based on HZO varactors in a parallel-plate MFM configuration [17,18], but due to the lack of experimental data at high frequencies, the dielectric relaxation was not considered. In fact, the results of studies of the high-frequency properties of HfO 2 are controversial.…”

Section: Introductionmentioning

confidence: 99%

RF-Characterization of HZO Thin Film Varactors

Abdulazhanov

Huynh

et al. 2021

Crystals

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A microwave characterization at UHF band of a ferroelectric hafnium zirconium oxide metal-ferroelectric-metal (MFM) capacitors for varactor applications has been performed. By using an impedance reflectivity method, a complex dielectric permittivity was obtained at frequencies up to 500 MHz. Ferroelectric Hf0.5Zr0.5O2 of 10 nm thickness has demonstrated a stable permittivity switching in the whole frequency range. A constant increase of the calculated dielectric loss is observed, which is shown to be an effect of electric field distribution on highly resistive titanium nitride (TiN) thin film electrodes. The C-V characteristics of a “butterfly” shape was also extracted, where the varactors exhibited a reduction of capacitance tunability from 18.6% at 10 MHz to 15.4% at 500 MHz.

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A mmWave Phase Shifter Based on Ferroelectric Hafnium Zirconium Oxide Varactors

Cited by 15 publications

References 14 publications

Understanding the Reliability of Ferroelectric Tunnel Junction Operations using an Advanced Small-Signal Model

Understanding the Reliability of Ferroelectric Tunnel Junction Operations using an Advanced Small-Signal Model

Electric field-induced crystallization of ferroelectric hafnium zirconium oxide

RF-Characterization of HZO Thin Film Varactors

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