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First results on a novel voltage controlled oscillator (VCO) in the lower gigahertz range, featuring excellent phase noise and high power efficiency are presented. The heart of the VCO is a recently reported novel miniature two-pole decoupled stacked bulk acoustic resonator (DSBAR) filter. With its single 180° phase transition over the 1 dB bandwidth, linear phase, and maximum 1 dB insertion loss, it provides stable single-mode operation over 45 MHz (≈3%) of tuning bandwidth and has negligible heat dissipation when operated at incident power levels of 100 mW or greater. The 1.55-GHz laboratory VCO prototypes operate at 5 V supply voltage, 50 mA supply current, 15 dBm of output power, and >;13% efficiency, demonstrating -84 and

Coupled resonator filters designed using a single-layer coupler require coupling materials with an acoustic impedance less than 5.0 MRayl. Carbon-doped oxide, with an acoustic impedance of 4.8 MRayl and an acoustic attenuation of 200 to 600 dB/cm at 1 GHz, can be used as a single-layer coupler to produce a competitive 2-stage coupled resonator filter for cellular handset applications in the gigahertz frequency range. The electrical response of our filter is superior to that of coupled resonator filters using a traditional acoustic mirror as the coupling element. We present an ultra-miniature 0.58 mm times 0.38 mm coupled resonator filter operating at a frequency of 2.15 GHz.

To realize the full potential of high density embedded ferroelectric memory, ferroelectric film thickness must be scaled below 100 nm to ensure that the capacitor operating voltage is compatible with advanced, low voltage logic transistors. In this article, we describe recent progress in the preparation of sub-100 nm thick Pb(Zr,Ti)O3 (PZT) thin films by metalorganic chemical vapor deposition on 200 mm wafers using an industry-standard processing platform. Within the full range of thicknesses investigated, 134–52 nm, capacitor operating voltage scales linearly with film thickness, yielding 71 nm thick films with a switched polarization (Psw) of ∼40 μC/cm2 at 1.2 V. Below ∼50 nm, PZT surface roughness makes further thickness scaling difficult. With improved surface morphology, however, even lower operating voltages should be feasible.

We present a robust, chip-scale packaged FBAR oscillator that is compatible with high volume manufacturing. The oscillator's extremely small size (area < 1 mm2, thickness = 0.23 mm) combined with an SMT-compatible pad design enables integration of the timing function in-package with a companion ASIC. We have measured tens of thousands of oscillators operating at a native frequency of 2.6 GHz and observe mean jitter less than 10 fsec (12 kHz to 20 MHz offset), with many devices better than 8 fsec. The mean phase noise is −158 dBc/Hz at 800 kHz offset and −118 dBc/Hz at 10 kHz offset. The device draws 18 mA at 3.3V, and the phase noise at all frequency offsets remains within 1 dB over the temperature range from −40 to 125°C. Far from carrier noise is set by the power delivered to the resonator. Due to the ability of the resonator to remain linear at high power, far-from-carrier phase noise is as low as −165 dBc/Hz. The sensitivity to acceleration of these oscillators is better than 0.1 ppb/g. Hermeticity tests carried out on the chip-scale package indicate that the oscillators behave with the same level of integrity as our standard FBAR filters. Preliminary studies on aging have determined an upper bound on frequency drift. Including contributions from supply and load sensitivity, temperature, and aging, total frequency drift is less than +/−200 ppm.

We present a FBAR oscillator that operates at 628MHz, achieves low jitter

The kinetics of deuterium doping of and removal from polycrystalline (Ba,Sr)TiO3 (BST) thin films during annealing were investigated using secondary ion mass spectrometry depth profiling, and the data were correlated to changes in the electrical behavior of the films. Results for deuterium doping of exposed BST films on a Pt bottom electrode layer are consistent with incorporation of deuterium interstitial defects at the BST/Pt interface and “upward” diffusion toward the film surface. The incorporation kinetics of deuterium in Pt/BST/Pt capacitors are more complex and are greatly enhanced by the presence of the Pt top electrode. Removal of deuterium from D2/N2-exposed Pt/BST/Pt specimens during oxygen recovery anneals appears to be limited by the rate of an interfacial reaction at low temperatures (200–250 °C). The pre-D2 exposure leakage current properties of the BST capacitors were found to be largely recovered when the deuterium concentration in the films was reduced to ∼1019 cm−3 during post-D2 oxygen...

We report the effect of top electrode structure on the electrical properties of ferroelectric Pb(ZrxTi1-x)O3 (PZT) capacitors. Samples with Ir/PZT/Ir or Ir/IrO2/PZT/Ir stacks were prepared using reactively sputtered Ir/IrO2 (top) and Ir (bottom) electrodes and MOCVD-deposited PZT on TiAIN/SiO2/Si wafers. Capacitor structures were patterned by plasma etching of the top electrode and show evidence for transient fence formation. Electrical measurements of the capacitors showed good ferroelectric properties (2Pr up to 38 μC/cm2, with leakage

The deposition temperature dependence of Ba0.7Sr0.3TiO3 (BST) thin film physical and electrical properties was investigated. Films were deposited between 250 and 500°C by electron cyclotron resonance (ECR) plasmaenhanced liquid source metalorganic chemical vapor deposition (MOCVD). Depositions were carried out in an oxygen plasma using the precursors Ba(thd)2•(polyamine), Sr(thd)2•(polyamine), and Ti(O-i-Pr)2(thd)2. With a constant ECR plasma power, composition and growth rate were independent of temperature within the full range investigated, in contrast to most thermally-driven CVD BST processes. Films grown above 350°C were crystalline as-deposited on Pt, and were (100)-textured. The dielectric properties depended strongly upon BST crystallinity, with a sharp increase in dielectric constant and its field dependence observed above 350°C. For slightly Ti-rich, 800A thick films, dielectric constants of 281 were obtained at 500°C, following a 550°C top electrode anneal in O2. Over the full deposit...

We present a fourth-design generation Free Running Oscillator and Voltage Controlled Oscillator using integrated bipolar circuitry in the lid wafer with a temperature-compensated FBAR resonator in the base wafer. The goal is to produce a high frequency, low-noise oscillator. Because there are ~15,000 oscillators per wafer, we can develop very sensitive testing procedures to study the oscillator behavior. For example, we have determined our frequency measurement accuracy and precision to be ~ 0.2 parts-per-million (1 σ), and our phase sensitivity floor to be less than -180 dBc/Hz. Measurements on package hermeticity, suggest that the oscillators behave with the same level of integrity as our standard FBAR filters.

We present the first IC oscillator using acoustically coupled FBAR's with a 3.75% tuning range. The tuning range is higher than previous low-power FBAR oscillators and wide enough to cover the individual ISM bands. The high Q of the resonator enables to achieve a phase noise of -144.35dBc/Hz at 1MHz offset with a carrier frequency of 1.55GHz and a power consumption of 11.7mW. The miniaturized coupled FBAR die is (500×540)μm2. The active area of the CMOS is (600x550)μm2.

We demonstrate a 2.6 GHz chip-scale oscillator that measured phase noise better than −150 dBc/Hz at 1 MHz offset and integrated jitter of just 25 fs. The part was designed with differential out and drives a 100 Ohm differential load with a mean voltage swing of 100 to 200 mV. The phase noise at 10 kHz offset is −110 dBc/Hz. The device runs at 3.3V and Idd is just over 9mA (including buffer). Another variant is designed to have an on-chip varactor allowing tuning of 615 ppm/V over the targeted 0.5 to 1.8 V tuning range. Here, the integrated jitter degrades by 2X at 0 V Vtune and we measured 85 fs jitter at 1.5 V Vtune. Still, the integrated jitter was well below 100 fs. The all-silicon packaged part is designed to directly solder down onto a PCB. There are no bond wires used in the assembly of this device. The height of the soldered part is under 0.25 mm, and the area of the die is less than 1 mm2. The oscillator uses a Zero Drift Resonator (ZDR) FBAR and we see about +/− 100 ppm temperature drift from −40C to +110°C. The design uses a cross-coupled architecture with the ZDR and is ac-coupled to a buffer amplifier.

Long-range oxygen motion has been observed in Pt/Pb(Zr,Ti)O3/Ir thin-film structures after electrical fatigue cycling at room temperature. Through an exchange anneal, isotopic 18O was incorporated as a tracer into bare Pb(Zr,Ti)O3 (PZT) films, allowing secondary ion mass spectrometry measurements of the tracer profile evolution as a function of the number of polarization reversals. Observation of 18O tracer redistribution during voltage cycling, which is presumably mediated by oxygen vacancy motion, was found to be strongly dependent upon the thermal history of the film. However, there was no strong correlation between the extent of 18O tracer redistribution and the extent of polarization suppression induced by voltage cycling. Our results suggest that oxygen vacancy motion plays, at most, a secondary role in ferroelectric fatigue of PZT thin films.

The measured switched polarization properties of integrated Pb(Zr,Ti)O3 (PZT) capacitors arrays have been found to show a small dependence on individual capacitor size in the range from 0.17 and 100 μm2. These thin (90 nm) PZT capacitors have low voltage switching properties with polarization saturation of

Acoustical attenuation and velocity parameters for Carbon Doped Oxide (CDO) thin films at GHz frequencies are needed to design Coupled Resonator Filters (CRF). CDO exhibits longitudinal acoustical impedance in the range of 2 to 11 MRayls, velocity of 2400 to 4000 m/s, and acoustical attenuation of 300 to 5000 dB/cm @ 1 GHz. A novel short loop acoustical technique is presented to make these measurements. An FBAR resonator, operating at the quarter wavelength (λ/4) frequency f cdo , excites a CDO thin film. The CDO is made λ/4 thick in order to de-couple the CDO film from the FBAR. From the measured thickness t CDO and λ/4 frequency of the CDO, the velocity v may be calculated: v=4t CDO f CDO . From the measured quality factor Q and wave number k=∞/v, the attenuation constant α ∼ k/(2Q) is calculated. By building matched λ/4 thick resonator/CDO film stacks at different frequencies, the CDO attenuation versus frequency is obtained. A linear (f1) attenuation, not the usual quadratic (f2), dependence on frequency is found. The measurement technique will be described in detail, as well as limitations on the range of validity. A series of CDO film compositions on FBARS were made. Synthesis of the CDO films was discussed previously [1]. A typical CDO film exhibited acoustical v=3250 m/s, impedance=4.7 MRayls, and α=2000 dB/cm @ 1 GHz, (f2) dependence. For well matched λ/4 FBAR resonators and CDO films, the short loop results were quite accurate. When the quarter wavelength condition of either the FBAR or CDO film was violated, there is a slight error in the velocity and attenuation measured. In either case the results are compared to those of values obtained by detailed analysis of the measured scattering parameters in a Mason equivalent circuit.

Recently, a new standard has been proposed to augment the performance of future Global Positioning System (GPS) receivers, and is generally referred to as the Global Navigation Satellite System (GNSS) band. By also requiring differential signals from the output of the filter to the cell phone receiver, further performance improvements can be obtained. To accommodate the new GNSS specifications and to provide single-ended to differential (SE-DE) mode conversion, new filter designs are required. In this work, we describe a two-stage, SE-DE filter design for GNSS that is based on coupled resonator filter (CRF) technology. The design provides insertion loss better than −2.5 dB over a frequency range greater than 56 MHz. Out-of-band rejection is greater than 40 dB from DC to 6 GHz, and better than 60 dB below 2 GHz. As a stand-alone filter, excellent phase and amplitude balance are achieved without the need for external inductors. In a frontend module consisting of the filter and an Avago LNA, we have measured >13 dB gain over the GNSS band. The module also shows excellent rejection and true differential output equivalent to surface acoustic wave filter solutions.

First results on a novel power efficient voltage controlled oscillator (VCO) in the lower GHz range, featuring excellent phase noise, high frequency accuracy and stability are presented. The heart of the VCO is a novel miniature two-pole De-coupled Stacked Bulk Acoustic Resonator (DSBAR) filter recently reported. With its single 180 deg. phase transition over the 1 dB bandwidth, linear phase and maximum 1 dB insertion loss it provides stable single-mode operation over 45 MHz (≈3%) of tuning bandwidth and negligible heat dissipation when operated at incident power levels of 100 mW and higher. The 1,55 GHz laboratory VCO prototypes operate at 5V supply voltage, 50 mA supply current, 15 dBm of output power and >13% efficiency demonstrating −83 and

Electrical degradation of (Ba, Sr)TiO3 (BST) thin films was investigated by annealing Pt/BST/Pt structures in D2/N2 and D2O-containing furnace ambients. Deuterium depth profiles were correlated to the current–voltage characteristics of the BST thin films. The dependence of the D distribution and leakage current density on the D incorporation method indicates that mobile, donor-type deuterium defects dissolve in large concentrations within BST thin films, and that their effects on leakage properties depend on the nature of their charge compensation. A mechanism is proposed for the leakage current increase after D2/N2 anneals, and good quantitative agreement between the theoretical results and experimental data is demonstrated.

Two filter applications, GPS and Wi-Fi, using bulk wave coupled resonator filters (BWCRF) are discussed. The device consists of two FBAR resonators stacked one on top of the other and separated by a thin de-coupling layer. We refer to this device as a De-Coupled Stacked Bulk Acoustic Resonator or DSBAR. These devices can be used as stand-alone filters or together with similar devices to create very small filters capable of single-ended to single-ended or single-ended to differential conversion. Also, due to the unique arrangement of the two FBAR one on top of the other, an impedance transformer can be made. Lastly, these devices have a very short “ring-down” time compared to “classic” FBAR filters, important for OFDM applications.

We present a filter for the 2.4 GHz ISM band that has both filtering and balun functionality to deliver a single ended to differential (SE2DE) filter response and 4:1 impedance transformation. We integrate the balun and filter response into a single chip using two FBAR resonators stacked one on top of the other and separated by a thin, low acoustic impedance material. True SE2DE behavior is achieved by dividing the bottom FBAR into two 100 Ohm resonators and hooking them in parallel to present a 50 Ohm impedance to the endpoint. The two 100 Ohm resonators forming the top of the stack are connected in series to present a differential output impedance of 200 Ohms. Since the entire device is not much larger than a single 50 Ohm resonator, the total die size is extremely small (much smaller than a typical FBAR half ladder filter utilizing 4 to 8 resonators).

A novel high isolation piezoelectric transformer operating in the UHF band is presented. The acoustically coupled transformer (ACT) is composed of thin film PZT transducers on both sides of an insulating substrate. The input transducer launches an acoustic wave through the insulating substrate to the output transducer in a pitch/catch mode to realize a 1:1 turns ratio. Appropriate series connection of multiple input transducers and parallel connection of the corresponding output transducers results in a transformer with an N:1 turns ratio. The ACT is fabricated using standard thin film and wafer scale fabrication techniques on a 150 mm diameter alumina wafer. The PZT transducers are deposited on Pt electrodes on both sides of the substrate by a sol-gel method. A backside photo-aligner is used to assure alignment of front and back side devices. Thousands of transformers can be made at once, thus eliminating costly one-off manufacturing. A novel differential electrode structure is used to apply the electric field to the PZT transducers without the need to etch the PZT film to reach the bottom electrode. Scattering (S) parameters of the ACT devices were obtained experimentally with a novel double-sided probe station that used air co-planar microprobes and a differential network analyzer. ACT transformers of 1:1 voltage ratio, with high DC isolation, and operating in the 20 to 200 MHz range are realized. The transformers exhibit a series of low insertion loss resonant peaks, spaced ~12 MHz apart, with |S21| as low as -1.2 dB when conjugate matched at the input and output ports. A temperature coefficient of frequency of -49 ppm/degC is measured. Power densities in excess of 400 Watts/cm3 are achieved. Dispersion diagrams for the allowed vibration modes are presented.

We demonstrate the bit functionality of a low-voltage, embedded ferroelectric random-access memory constructed using a 130 nm gate and five-level Cu/FSG interconnect process. By inserting the two additional masks required for the eFRAM module into this logic flow, we have co-integrated ferroelectric memory and SRAM on a single wafer.

Switched polarization fatigue was investigated for CVD PZT ferroelectric films of thickness

Summary form only given. High-density, embedded ferroelectric memory (FeRAM) has the potential to replace embedded flash, embedded DRAM, and non-cache SRAM and could be a key enabler for future system-on-a-chip applications. Despite this appeal, the evidence that ferroelectric capacitors can be scaled to the submicron regime has been limited. In this paper, we report the fabrication and electrical properties of submicron PZT capacitors formed using both planar bottom electrodes and W plug contact structures. We observe that the aggregate saturation polarization value is nearly independent of individual capacitor area in the measured range from the contact-limited size of 0.12 /spl mu/m/sup 2/ to 10/sup 4/ /spl mu/m/sup 2/. This result suggests that high-density, embedded FeRAM technology may be feasible.

We have demonstrated that the scaling of IrO x (Pb(Zr, Ti)O3:PZT)/Ir capacitors can be extended into the submicron regime. The submicron IrO x /PZT/Ir capacitors were fabricated using a one-mask stack-etch process, integrated with an SiO2 interlayer dielectric, and contacted with Al metallization. The aggregate electrical properties of integrated PZT capacitor arrays are shown to be nearly independent of individual capacitor area in the range between 102 µm2 and 0.12 µm2. In particular, switched polarization values of more than 30 µC/cm2 were obtained for PZT capacitors with an individual capacitor area of 0.12 µm2. This result suggests that the lateral scaling can be achieved down to 0.1 µm2. Through the use of appropriate diffusion barriers, hydrogen-robust submicron PZT capacitors are obtained. No degradation in ferroelectric properties of submicron PZT capacitors was observed under the test conditions. These results suggest that PZT capacitors can be integrated into a standard complementary metal oxide semiconductor (CMOS) process flow with minimal degradation.

New metal contaminants, such as Pb, Zr, and Ir, introduced during ferroelectric nonvolatile memory (FeRAM) fabrication are of great concern hecause of their potentially adverse effects on complementary metal oxide semiconductor device characteristics. Numerous routes for cross-contamination exist in a Si wafer fab. In this study, we focus on the transfer of elements between the contaminated wafer handling system of a typical shared tool and the back side of clean wafers. Specifically, the potential for transferring Pb, Zr, Ti, and Ir from a contaminated surface to clean wafers was investigated. It was found that, after exposing a robotic handler and chuck directly to the surface of Pb(Zr,Ti)O 3 films, clean wafers that were subsequently run through the tool acquired a maximum of 1.1 × 10 11 , 9.0 × 10 10 , and 5.1 × 10 10 atoms/cm 2 of Pb, Zr, and Ti, respectively. After exposing the tool to Ir films, significantly less Ir transferal was observed (1.0 X 10 9 atoms/cm 2 ). In all cases, cycling a series of clean wafers through the tool led to a rapid decrease in the quantity of transferred contaminants, and was the most effective method for eliminating these elements altogether. Moreover, the Pb, Zr, Ti, or Ir contaminants transferred in this way were easily removed using a traditional pregate surface cleaning process.