Derwent Classification System: Semiconductors and Electronic Circuitry

Includes semiconductor components per se, their manufacture and circuitry. Circuits using electronic components are included, eg filters and oscillators.

U11 Semiconductor Materials and Processes (C30B, H01L) Materials, substrate and layer processing, packages and mountings, assembly, testing, and handling aspects of all semiconductor devices, included in U12, U13, U14. Aspects of manufacture specific to devices such as LEDs, lasers, solar cells and especially thick film and hybrid circuits are covered in U12 and U14.
U12 Discrete Devices (H01L) Individual semiconductor devices, as either discrete components or specific parts of integrated circuit. Examples are LEDs, including LED arrays, semiconductor lasers, photovoltaic cells and arrays, discrete photodetectors, semiconductor transducers, diodes, capacitors, bipolar transistors, thyristors, unipolar transistors eg. FET, HEMT, and quantum interference devices. Also, defines specific application of inventions in U11.
U13 Integrated Circuits (H01L) Integrated circuit structures eg, CMOS, BICMOS, optoelectronic IC, wafer scale integration. Analogue circuits. Digital circuits, especially with matrix arrays eg. memory, programmable logic and gate arrays. Solid state image sensors eg. CCD. Not used for routinely integrated circuitry eg. logic gates, or for IC application which do not claim actual IC novelty.
U14 Memories, Film and Hybrid Circuits (G11C, H01L) Digital memories including magnetic, optical, semiconductor, ferroelectric analog memories. Testing of memories. Thermoelectric devices. Superconductive materials and devices. Thin film arrays and layers. Thick film and hybrid circuits including multilayer ceramic wiring boards. Electroluminescent light sources. Passive displays, especially liquid crystal display.
U21 Logic Circuits, Electronic Switching and Coding (H03K, M) Basic logic circuits, eg AND-gates. A/D and D/A conversion. Delta modulation, coding, code conversion, error detection and correction. Pulse counters, frequency conversion. Electronic switching circuits.
U22 Pulse Generation and Manipulation (H03K, L) Rectangular wave oscillators, pulse generators, (astable, bistable, etc). Pulse shapers. Digital waveform synthesizers. PAM, PPM, PFM, PDM (modulation and demodulation aspects). Digital filters. DSP.
U23 Oscillation and Modulation (H03B-D, H03L) Oscillators, mixers. Amplitude and angle (de)modulation. Frequency and phase comparators. PLLs.
U24 Amplifiers and Low Power Supplies (H03F, H03G, G05F, H02M) DC, LF and HF amplifiers, parametric, magnetic, dielectric amplifiers. Gain control. Volume compression or expansion. Limiters. Voltage and current stabilisation, power supplies, converters, inverters, rectifiers. Low power protection.
U25 Impedance Networks and Tuning (H03H, H03J) Tone or bandwidth control. Impedance converters. Analogue filters (active and passive). Voltage dividers, attenuators, impedance matching, baluns. Tuning circuits. AFC.