Inquiries regarding the use of the book should be addressed to the Rights and Permissions Department of INTECHOPEN LIMITED (email@example.com). At the end of the chapter, the chip manufacturing process is briefly described.
129 CMOS Integrated Circuits for Various Optical Applications
Back in the old days, about five decades ago, the number of transistors found in a chip, even at its highest count, was less than 5000. The Intel 4004 4-bit microprocessor, manufactured in the large-scale integration (LSI) era, consisted of only 2300 transistors and operated at a maximum clock rate of 740 kHz.
A brief history
Both Kilby and Noyce shared patent rights for the invention of the integrated circuit. In 2000, Kilby was awarded the Nobel Prize in Physics "for his contribution to the invention of the integrated circuit".
The field-effect transistors
- The MOSFET
- The FinFET
To highlight technological progress in the IC industries, each decade since the inception of the semiconductor transistor has been designated as a different era. The channel is commonly called the inversion layer since the accumulated charges in the channel are opposite to those of the substrate.
IC design flow
- Behavioral representation
- Logic circuit representation
- Layout representation
In the early stages of IC design, it is important to be specific about the chip's functionalities. SystemVerilog hardware description language (HDL) is used to define the behavior of the IC chip.
- Well formation
- Device isolation
- Transistor making
The process flow of manufacturing a planar MOSFET is summarized in the following sections, and it is also graphically depicted in Figure 5. The process of chip manufacturing can be broadly separated into five stages, i.e. i) well formation, (ii) device isolation, (iii) transistor making, (iv) interconnection and . The CVD process is applied to deposit a layer of silicon nitride Si3N4 on the surface of the substrate (Figure 5 (xviii)).
The nitride film is etched to form sidewall spacers on both sides of the gate (Figure 5 (xix)). However, the threshold voltage (VTH) of the MOS devices is not lowered at the same rate.
Low-voltage design techniques and approaches
- MOS transistor in sub-threshold operation region
- Bulk-driven design approach
Using the small-signal model, the transition frequency fT,BD of the BD MOS transistor can be obtained. The transfer function and current gain of the BD MOS transistor can be expressed by Eq. Most.
Design examples of low-voltage analog ICs
- BD current mirrors
- BD differential amplifier
- Variable-gain amplifier (VGA) .1 Description of BD VGA
- Low-voltage BD comparator
- Ultra-low-voltage BD charge pump .1 Description of the BD charge pump
- Evaluation of the proposed LV circuits
The analog core of the proposed circuit is depicted in Figure 12 along with the dimensions of the devices. The small-signal model gives an Eq. 25), which defines the voltage gain of the second stage.
The selected parameters of the proposed VGA, voltage comparator and charge pump are depicted in Figure 19. Measured and simulated parameters of the proposed circuit topologies on the prototype chip. a) VGA frequency response, (b) Comparator transfer characteristics, (c) Charge pump efficiency.
Power consumption issues
The SCEs of the MOSFETs are important when the channel length becomes comparable to the width of the depletion region. In fact, the problem lies in the rate at which the transistor passes from the off to the on state as a function of the gate voltage.
Tunnel field-effect transistors
- Electronic properties of graphene
- Electronic properties of 2-D TMDs
This requires a strong modulation of the channel bands near the gate and a very thin channel barrier. They can be assembled to form a new class of tunneling transistors based on an interlayer tunneling occurring in the direction normal to the plane of 2DMs .
TFETs based on 2-D material vdWHs
- Vertical vdWH TFET
The high-k dielectric used in this device, HfO2, also provided the added benefit of improving the mobility of monolayer MoS2. Top gating with a high-k dielectric was also used in a p-type FET with an active channel made of WSe2 monolayer flakes, which showed a room-temperature hole mobility of 250 cm2/(Vs), close to 60 mV/dec SS, and a 106ION/IOFF ratio .
Quantum transport modeling
To evaluate^ the time evolution of the Green's function G r, t; rð 0, t0Þin the Heisenberg picture, the time derivative of G r, t; rð 0, t0Þ can be obtained. The greater and lesser Green's functions are directly related to the hole density and electron density in the system. The coupling between Green's function and the Poisson's equation must be solved self-consistently.
- What is polymorphism?
- The role of polymorphism in OFET
Individual defects in inas/ingaassb/gasb nanowire tunnel field-effect transistors operating below 60 mv/decade. New vertical hetero and homo junction tunnel field effect transistors based on multilayer 2D crystals. An organic field effect transistor (OFET) is a transistor that uses an organic semiconductor thin film as the active layer in its channel [1, 2].
Methods of polymorph control in organic semiconductors
- Solvent control
- Temperature control
- Crystallization through kinetics control
- Templating via heterogeneous nucleation
- Postdeposition control
- Other methods
The charge transport property of organic semiconductors is sensitive to molecular packing, where a small change in molecular packing can result in a huge difference in charge carrier mobility . The thermodynamic polymorphic selection is mostly observed by deposition of organic semiconductors by physical vapor transport (PVT) processes . In other words, substrates and additives can act as templates to change the crystal structure of organic semiconductors.
Charge transport in OFETs with different polymorphs
- Theoretical studies
- Thin-film transistors with different polymorphs
- Single-crystal transistors with different polymorphs
In a study by He et al., the ribbon-shaped β-phase crystals were grown on various substrates such as Si/SiO2 by sublimation in ambient air pressure . Single crystal transistors were produced where the α-phase and β-phase crystals exhibited hole mobilities of 8.5 and 18.9 cm2 V−1 s−1, respectively. The electronic couplings of adjacent molecules in α-phase and β-phase crystals were calculated by the quantum chemical calculations.
Conclusion and outlook
High performance single crystal organic field effect transistors based on two dithiophenetrathiafulvalene (DT-TTF). Air-stable n-channel organic single-crystal field-effect transistors based on core-chlorinated naphthalenediimide microstrips. Single crystal field effect transistors of new Cl(2)-NDI polymorph processed by sublimation in air.
Thin-film transistors (TFTs)
- OFET architectures
- Fundamentals of OFET operation
Accordingly, the thin film transistor design has been shown to be the preferred structure for low conductivity materials such as organic semiconductors. In an n-channel OFET operating in accumulation (enhancement) mode, when a positive voltage bias is applied to the gate terminal, electrons begin to accumulate at the dielectric/semiconductor interface, which forms a current path (channel) between the source and drain contacts. L ½ðVGS�VtÞVDS�, (1) where C is the gate capacitance per unit area, μlini is the charge carrier mobility in the linear regime, W is the channel width, and L is the channel length of the device.
Low voltage OFETs
- Dielectrics: background
- Dielectrics in electronic devices
- Dielectrics in low voltage OFETs .1 Organic dielectrics
- High-k metal oxide deposition techniques .1 Radio frequency (r.f.) magnetron sputtering
- Sources of ionizing radiation
- Exposure, dose and dose equivalent
- Interaction of ionizing radiation with matter
Consequently, the net electric field is reduced due to the polarization of the dielectric medium. The relationship between the energy gap and the dielectric constant of the most common inorganic high-k materials is illustrated in Figure 4. The absorption characteristic of the target material (i.e. skin tissue) leads to the concept of absorbed dose.
Detectors of ionizing radiation
- Solid-state methods for sensing ionizing radiation
- MOSFET sensors
The photoelectric effect occurs when the energy of a photon exceeds the binding energy of the electron in its shell. In this case, the electron is ejected from the atom with a kinetic energy equivalent to the energy of the incident photon minus the binding energy of the electron. On the one hand, ionizing radiation induces electronic states (traps) at intermediate energies between the valence and conduction bands of the semiconductor.
Organic electronics and their relevance for tissue equivalences In order to track correctly the mechanisms of energy release in skin tissue, the
- Dosimetry based on organic field-effect transistors
- Dosimetry based on organic diodes and single layered structures
The threshold voltage was negatively shifted due to the accumulation of positive charge on the silicon dioxide . Later the same group investigated the Pentacene OFET using the similar device structure shown in Figure 3. Silicon nitride as a passivation layer was used to protect the organic materials from. a) Schematic of a pentacene OFET in bottom-gate end-contact configuration with interconnected source and drain electrodes using a silicon nitride passivation layer and (b) Id-Vg characteristics for a pentacene OFET with exposure to increasing dose of ionizing radiation . The sensitivity of TIPS-Pentacene transistors was the highest among similar organic transistors in the literature, 3 V/Gy .
- CMOS chipsets for HDMI active optical cables
- CMOS Rx IC for LiDAR
Third, the input-referenced equivalent noise current spectral density of the VCF input stage is given by . The input impedance of the MC-TIA was also measured to be in the range of 30-80Ω within the bandwidth. Considering the inherent oscilloscope noise of 1.01 mVrms, the integrated input-referenced noise current of the MC-TIA is given by
Thus, various architectures have been proposed in the literature to improve the areal efficiency of SOT-MRAM. Manipulating the FL direction to be either parallel (P) or anti-parallel (AP) to the PL magnetization direction determines the electrical resistance state of the MTJ to be either low resistance (RP) or high resistance (RAP). Thus, various SOT-MRAM cell designs have been proposed in the literature to improve the areal efficiency of SOT-MRAM.
- Conventional SLC SOT-MRAM
- MLC SOT-MRAM
The non-diode-based SOT-MRAMs in the literature include the conventional single-level cell (SLC) SOT-MRAM, as shown in Figure 2(a), and two multi-level cell (MLC) proposals depicted in Figures 2(c) and (d). However, it is required to distinguish between four different resistance states, as opposed to the only two states that exist in the conventional SLC. However, it is required to distinguish between four different resistance states, as opposed to the only two states that exist in the conventional SLC.
- SLC diode-based SOT-MRAM
- Multi-bit per cell dedicated diode (MBC-DD) SOT-MRAM
- Multi-level cell shared diode (MLC-SD) SOT-MRAM
This section presents the various diode-based or selector-based SOT-MRAM proposals in the literature. The RWL of the target D-MTJ is then connected to the sense amplifier to forward bias the diode and read the data stored in the MTJ, as shown in Figure 5(b). Consequently, similar to MBC-DD in the write operation, the WWL of the row that includes the requested cell is asserted high.
- Cell-level evaluation
- System-level evaluation
The impact of the smaller cell area is also evident while comparing the different MRAM technologies, as shown in Figure 10(b). Area comparison of the STT-MRAM, conventional, SLC-diode-based, S-MLC, P-MLC, MLC-SD and MBC-. Comparison of the SRAM, STT-MRAM, conventional, SLC diode-based, S-MLC, P-MLC, MLC-SD and MBC-DD SOT-MRAMs for different capacities relative to SRAM from (a) cache hit/miss energy per access perspective and (b) cache write dynamic energy per access perspective.
Through the Looking Glass - 2018 Edition: Trends in Solid-State Circuits from the 65th ISSCC. It also uses energies from the PET pulses to measure the depths of interactions (DOIs) [1-3]. The readout of the PET pulses generated by the photodetectors produces a shift in the baseline of the signal.
Materials and methods
- The detection ring
- Digital conditioning of the PET pulses
- The BLR
- The hybrid interpolator
- The experimental setup
A certain number of sensors are used in a detection ring "3". The front-end electronics, located in the detection sensors "4," further prepare and process PET pulses originating from photodetectors. This indicates that the radioactive tracer, 22Na, is displaced by a robotic arm with respect to the used crystal pour intellator matrix "6". The gap between successive relocation steps remains equal to 1 mm. Signal selection and address encoding block "10" is used to outputs of "8a" and "8b." The selected pulses are then added using the adder circuit "9". Finally, the selected pulses provided by "10" and their sum, provided by "9" are simultaneously digitized using an oscilloscope.
VHDL implementation and synthesis on FPGA
The system includes a sensor, consisting of four 3�3�60 mm3 LYSO crystals, surrounded on both sides by 3�3 mm2 arrays of Hamamatsu MPPCs, "7a" and "7b." The MPPC array consists of four MPPCs of 3�3 mm2 area that match the scintillators used. The front-end electronics modules, "8a" and "8b," control the pulses coming from both MPPC dies "7a" and "7b." They realize amplification, selection and delay addition. Later, when the hybrid interpolation module is characterized, these pulses, obtained at a frequency of 3.2 GHz, are used as a reference.
- The characterization of BLR
- The characterization of hybrid interpolator .1 The leading-edge selector
- Comparison of the hybrid interpolator with a conventional interpolator The effectiveness of the suggested hybrid interpolator is also compared with a
Due to the influence of various deviations, for a fixed location between the radio tracer and the crystal scintillator matrix "6", the incoming pulses show a peak amplitude distribution of about 25% among them. For designed hybrid interpolator, the average RMSDE value is 13.6μV. The interpolated signal is used for post-timestamp estimation. In this case, using the proposed hybrid interpolator, the temporal resolution of the selected section is improved 16-fold.
Discussion and conclusion