## 6 Nanorobot Architecture
### Chemical Sensor  
Manufacturing silicon-based chemical and motion-sensor arrays using a two-level system architecture hierarchy has been successfully conducted in the last 15 years. Applications range from automotive and chemical industry, with detection of air to water element pattern recognition, through embedded software programming, and biomedical analysis. Through the use of nanowires, existing significant costs of energy demand for data transfer and circuit operation can be decreased by up to 60% [67]. CMOS-based sensors using nanowires as material for circuit assembly can achieve maximal efficiency for applications regarding chemical changes, enabling new medical applications [21, 73, 74].  
Sensors with suspended arrays of nanowires assembled into silicon circuits, decrease drastically self-heating and thermal coupling for CMOS functionality [75]. Factors like low energy consumption and high-sensitivity are among some of the advantages of nanosensors [76]. Nanosensor manufacturing array processes can use electrofluidic alignment to achieve integrated CMOS circuit assembly as multi-element systems [67]. Passive and buried electrodes can be used to enable cross-section drive transistors for signal processing circuitry readout. The passive and buried aligned electrodes must be electrically isolated to avoid loss of processed signals. For the nanorobot architecture, the antibody anti-digoxigenin is included for modelling the IC biosensor; the antibody serves to identify higher concentrations of proteins that couple alpha-NAGA isoforms to intracellular bloodstream signaling [45]. The nanobiosensor provides an efficient integrated way for nanorobots identifying the locations with occurrences of alpha-NAGA. Enzyme secretion from cell hostage produces alpha-NAGA overexpression, which is denoted by changes of gradients in the bloodstream. Therefore, an efficient prognostic can be achieved, even before symptomatic reactions, helping to fight a virus outbreak. Carbon nanotubes serve as ideal materials for the basis of a CMOS IC nanobiosensor [67, 77, 78].  
Some limitations to improving BiCMOS (bipolar-CMOS), CMOS and MOSFET methodologies include quantum-mechanical tunneling for operation of thin oxide gates, and subthreshold slope. However, the semiconductor branch has moved forward to keep circuit capabilities advancing. Smaller channel length and lower voltage circuitry for higher performance are being achieved with biomaterials aimed to attend the growing demand for high complex VLSIs. New materials such as strained channel with relaxed SiGe (silicon-germanium) layer can reduce self-heating and improve performance [79]. Recent developments in three-dimensional (3D) circuits and FinFETs double-gates have achieved astonishing results and according to the semiconductor roadmap should improve even more. To further advance manufacturing techniques, silicon-on-insulator (SOI) technology has been used to assemble high-performance logic sub 90 nm circuits [80]. Circuit design approaches to solve problems with bipolar effect and hysteretic variations, based on SOI structures, have been demonstrated successfully [79]. Thus, while 10 nm circuits are currently under development, already-feasible 45 nm NanoCMOS ICs represent breakthrough technology devices that are currently being utilized in products.