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Recent advances of devices and circuits have made CMOS (Complementary Metal Oxide Semiconductor) integrated circuits technology an alternative for realizing capable and affordable THz systems. Coherent detection up to 410 GHz and incoherent detection up to 10 THz as well as an almost fully integrated receiver working from 225–280 GHz have been demonstrated using CMOS. Despite the fact that f max of NMOS transistors has peaked around 320 GHz, it should be possible to coherently detect signals at frequencies beyond 1 THz and with some straightforward modification of processes, to incoherently detect signals at 40 THz in CMOS.

An 840-GHz Schottky diode detector is integrated with an analog lock-in amplifier in 130-nm bulk CMOS. The integrated lock-in amplifier can support a modulation frequency of up to 10MHz with a gain of 54dB, a dynamic range of 42dB, and an input referred noise of less than 10 nV/√Hz at modulation frequencies higher than 100kHz. The integrated lock-in amplifier occupies an area of 0.17 mm2 and consumes 4.9mA from a 1.2-V supply. The detector and on-chip lock-in amplifier combination was used to form terahertz images.

An 820-GHz 8×8 imaging array of diode-connected NMOS transistor detectors, and 5-, and 10-THz fundamental Schottky diode detectors are demonstrated in a 130-nm bulk CMOS process. Measured mean optical responsivity (Rv) of 2.6kV/W and mean optical NEP of 36pW/Hz1/2 at a modulation frequency of 1MHz are achieved for the 820-GHz imaging array. The NEP is more than 2.5X lower than that of the previously reported NMOS terahertz imaging arrays. The fundamental electronic detection of Far-Infrared radiation up to 9.74THz is also reported. A peak Rv of 383 at 4.92THz and a peak Rv of 14V/W at 9.74THz have been measured using a free electron laser. The Rv at 9.74THz is 14X of that for the previously reported highest frequency electronic detection. The shot noise limited NEP at 4.92 and 9.74THz is ∼0.43 and ∼2nW/VHz, respectively.

An integrated chain composed of an 195-GHz oscillator with frequency doubled output at ~390 GHz followed by two cascaded ÷2 injection locked frequency dividers with output frequency of ~49 GHz is demonstrated in 45-nm CMOS. The peak power radiated at ~390 GHz by an on-chip antenna is ~2 μW. This work indicates it is possible to phase-lock submillimeter wave signals in CMOS. Polysilicon Gate separated Schottky diodes that can be fabricated without any process modifications in a foundry 130-nm CMOS process are utilized to implement 280-GHz and 860-GHz detectors for imaging. A fully-integrated 280-GHz 4×4 imager array exhibits measured NEP of 29pW/Hz1/2 and responsivity of 5.1kV/W (323V/W without the amplifier). The 860-GHz detector without an amplifier achieves responsivity of 273V/W and NEP of 42pW/Hz1/2.

Using Polysilicon Gate Separated Schottky Diode structures that can be fabricated without any process modifications in a foundry digital 130-nm CMOS process, cut-off frequency of ~2 THz has been measured. In addition, exploiting the complementary of CMOS technology, an antiparallel diode pair with cut-off frequency of ~660 GHz consisting of an n-type and a p-type Schottky diode has been demonstrated in the same 130-nm CMOS process. Using the diodes, a frequency doubler and a tripler have been demonstrated. Additionally, the diodes have been utilized to implement 280-GHz and 860-GHz detectors for imaging. A fully-integrated 280-GHz 4×4 imager array exhibits measured NEP of 29pW/Hz1/2 and responsivity of 5.1kV/W (323V/W without the amplifier). The 860-GHz detector without an amplifier achieves responsivity of 355V/W and NEP of 32pW/Hz1/2. The NEP at 860GHz is 2X better than the best reported performance of MOSFET-based imagers without a silicon lens attached to the chip.

Schottky-barrier diodes fabricated in CMOS without process modification are shown to be suitable for THz imaging. Two THz imagers using a 130-nm digital CMOS technology are demonstrated. A fully-integrated 280-GHz 4×4 imager array exhibits a measured NEP of 29 pW/Hz1/2 and a responsivity of 5.1kV/W (323 V/W without the amplifier). For the first time, electronic-scanning multi-pixel imaging is demonstrated in a setup that does not require bulky and costly optical lenses and mirrors. A second detector operating at 860 GHz is also demonstrated. The detector without an amplifier achieves responsivity of 355 V/W and NEP of 32 pW/Hz1/2. It is shown that the comparable responsivity and NEP as that of 280-GHz detector is due to the improvement of patch antenna efficiency at 860 GHz. The NEP at 860 GHz is 2X better than the best reported performance of MOSFET-based imagers without silicon lens attached to the chip.

Millimeter and sub-millimeter-wave imaging using solid-state circuits is gaining attention for security and medical applications. To lower cost and increase integration, MOSFETs in CMOS are being investigated for implementing broadband detectors [1–3]. However, neither measured noise-equivalent power (NEP) nor noise floor of the imager was given in [1]. Although NEP of 17pW/Hz1/2 was achieved at 650GHz in [2], an external lens was attached to the 65nm SOI CMOS chip. In [3], an NEP of 66pW/Hz1/2 was measured at 1.05THz using 65nm CMOS without a lens attached to the chip. Additionally, although the efforts reported in [1–3] realized an array, none demonstrated the image-array function. As an alternative, polysilicon-gate-separation (PGS) Schottky-barrier diodes (SBD) with cut-off frequency of ∼2THz were fabricated in CMOS without process modifications [4] and were used to demonstrate a 280GHz detector with NEP of 30pW/Hz1/2 [5,6]. To significantly enhance the scanning speed, a 16-pixel 280GHz SBD imager is fabricated and its array function is reported in this paper. The imager including baseband amplifiers achieves responsivity of 5.1kV/W and NEP of 29pW/Hz1/2. More importantly, its operation was demonstrated in a setup that requires no mirror or lens that is bulky and costly. Next, an 860GHz SBD detector is demonstrated with a measured non-amplified responsivity of 355V/W and NEP of 32pW/Hz1/2. This NEP is ∼2X lower than the best reported work in CMOS [3]. Both chips are fabricated in a 0.13μm logic CMOS. The results suggest a path for high performance, compact and affordable sub-millimeter-wave and terahertz CMOS imagers using SBDs.

Intra coding is used for reducing the spatial redundancy in video coding. H.264/AVC supports several MB (Macroblock) predictions for Intra coding. These Intra predictions have also several directional prediction modes, which significantly improve Intra coding efficiency, but increase the encoding complexity. In this paper, a fast Intra prediction mode decision algorithm is proposed for the H.264/AVC Intra coding. The proposed algorithm selects one representative prediction mode among all intra predictions using the existing DCT and quantization schemes of H.264/AVC, and only the representative mode is used for RDO (Rate Distortion Optimization) process. The experimental results show that the proposed algorithm achieves an encoding time saving of 64% with negligible loss of PSNR (Peak Signal-to-Noise Ratio).

To reduce spatial redundancies in intra coding, Intra 4times4 mode provides nine directional prediction modes for every 4times4 block. In this paper, an adaptive intra mode bit skip method is proposed to improve coding efficiency in intra coding. The proposed method improves coding efficiency and reduces encoding complexity. Experimental results show that the average bit-rate reduction of 2.86% and 6.58% are achieved at the medium bitrate and low bitrate, respectively. In addition to that, encoding complexity is saved about 42% at the QP values of 27 and 32.

C. eleganspsila crawling locomotion including simple running and turning is analyzed with a mathematical model. C. elegans moves forward and backward by propagating dorso-ventral contraction waves toward the opposite direction of its movement. For straight run, the worm maintains a constant amplitude and period in its body curvature. While it changes these quantities during smooth turn. Two types of smooth turn are described theoretically based on the experimental observation. One has the turning strategy to increase both of amplitude and period of the curvature. The other is characterized by decrement of these parameters. Our results may contribute to understanding the lateral undulation of other smooth body animals like snakes and these could further be applied to the developments of bio-inspired robots.

We have investigated the crystalline structure, dielectric, ferroelectric and piezoelectric properties of the MBi/sub 4/Ti/sub 4/O/sub 15/ (M=Sr, Ca, Sr/sub 0.5/Ca/sub 0.5/) ceramics. The remanent polarization(P/sub r/) of SrBi/sub 4/Ti/sub 4/O/sub 15/(SBT) and CaB/sub 14/Ti/sub 4/O/sub 15/(CBT) ceramics was 2.2 /spl mu/C/cm/sup 2/ and 0.3 /spl mu/C/cm/sup 2/, respectively. The k/sub t/ of SBT and CBT OF ceramics exhibited a low value( 2000) compared to that of PZT(1000). The changes of dielectric, ferroelectric and piezoelectric properties in these ceramics have been originated from the lattice distortion of BO/sub 6/ oxygen octahedra according to the size of ion radius into A site which are represented from (Bi/sub 2/O/sub 2/)/sup 2+/(A/sub n-1/B/sub n/O/sub 3n+1/)/sup 2+/ in the bismuth layered structure.

Summary form only given, as follows. Advanced integrated circuit packaging processes require high bondability and reliability between various mating surfaces and a key factor affecting this requirements is the surface cleanliness. Contaminants degrading the adhesion property include organic or oxide layers and these impurities should be thoroughly removed before the bonding process. Plasma can be used for this purpose and has many potential advantages-reduction of processing waste, cleaner surface, controllability and a dry process, in comparison to chemical cleaning. A nonthermal plasma generated at atmospheric pressure has been used in cleaning a surface of wire bonding substrates and flip chip bumps widely used in todays packaging industry. The relation between the processing parameters (processing time, gas composition, additional UV exposure) and bonding characteristics has been investigated.