Circuit engineering solutions for high - temperature analog microcircuits in extreme environmental conditions

. The current geopolitical situation and import – substitution challenges facing the domestic electronics industry require the creation of devices capable of reliably functioning in extreme environmental conditions, at particularly high temperatures. When developing electronic devices that must function reliably in temperature range beyond the usual values, developers should rely on cooling , active or passive. There may be situations when cooling is impractical or impossible. The operation of the device in special temperature range, in some situations, makes perfect sense if it provides reduction in the cost of the device or increase in its reliability. In such situations, it is necessary to solve many complex problems, including semiconductor manufacturing technology, design and testing methods. The article examines the issues of creating high – temperature electronics components necessary for the long-term development of the domestic oil – and – gas and aerospace industries. Creation of import-substituting technologies for intelligent wells makes it possible to reduce significantly the cost of equipment. In aerospace industry, this problem is even more actual: the cost of "western" computing devices for use in space reaches half million euros, and under the conditions of sanctions, its purchase may not be available, while similar import-substituting domestic device is up to 10 times cheaper. Flights to near and far space require, in addition to high radiation resistance, the reliability of all spacecraft systems in the wide temperature range. Article presents technical characteristics of the main analog chips designed to operate at temperatures up to +125 ° C.

In XXI century, there is rapid development of high-temperature electronic components necessary in the production of vehicles, aviation, rocket-and-spacecraft, in development of new oil-and-gas fields, forexample, when drilling deep intelligentwells, etc.Many foreign manufacturers are engaged in the designandproduction of high-temperature electronics components.Therefore, Texas Instruments company [12] produces microprocessors SM320F28335-HT (32-bit signal microcontroller operating in the temperature range from -55 to +210 °C) and SM320F2812-HT (32-bit microcontroller, temperature range from -55 to +220 °C).
Atmel company [13] produces high-temperature drivers operating at transient temperatures up to 200 °C in environment up to +150 °C; CISSOID company [14], specialize in design of high-temperature electronic components, including ADCs (analogto-digital converters) operational amplifiers, voltage regulators, transistors, pulse generators, key drivers, power supply chips, etc.These components are operable at extreme temperatures from -55 to +225 °C, under powerful external influences of vibrations and mechanical shocks, temperature differences of almost 300 degrees, etc.Some components have been tested by NASA at extreme temperatures of near space from -195 to +400 °C, for use as part of rocket and space devices.

Need for high-temperature components for oil-and-gas wells.
Oil-and-gas production in our country is most important industry, and the imposition of sanctions restrictions by "west" on the supply of electronic components to Russia has led to increase in the number of new developments by domestic researchers.
Development of high-technological intelligent well system (intelligent well, IW) [15][16][17][18] is timely and urgent task today, involving remote control of well flow and optimization of oil-and-gas productionperformance, as well as monitoring of well parameters in real time.IW technology provides the increase in the efficiency of oil-and-gas production: reducing the time to restore the well, reducing the cost of its commissioning, minimizing the need for human personnel to interfere with the automatic operation of the well, as well as the safety of its operation.The working conditions of electronic components inside the well are extreme: operating temperature exceeding +150 °C, huge pressure, aggressive external environment and the presence of numerous steel valves and valves for its control, etc.
The technology is becoming more successful, and the requirement of compatibility, for example, of control systems associated with offshore underwater oil-and-gas production (Figure1) with IW technology has become standard.IW systems are largely new, and it is not yet clear whether they can provide reliability guarantees based on the short history of their practical application.The reason for the introduction of IW systems to manage the entire process of oil-and-gas production was an increase in the actual pace of work at the fields being developed.However, high efficiency of these systems is possible only when the system reaches the required indicators of reliability and safety of operation, in the absence of serious accidents.To determine the required characteristics, various parameters should be considered, among which are the capital costs of equipment and new technologies, and the consequences caused by system failure.These parameters are very different in different oil and gas fields, and depend on specific conditions.
In order to achieve the reliability of intelligent well control system, as well as monitoring its condition, the designed electronic components need to be based on such an architecture, which, at its core, includes high fault tolerance of circuitry and redundant solutions.Such decisionsare used in the process of designing andconstructing control systems for all types of oil and gas wells, including production and injection wells.
Special component of intelligentwells system is their telemetry equipment, which includes both ground and underground blocks.The appointment of telemetry devices is to control the operation of submersible electric motor, trackingand monitoring the parameters of the external environment in the bottom of the well; diagnosticsof various failures and malfunctions incidents, prevent potential accidents and equipment breakdowns (for example, drilling equipment may become clogged, which leads to its failure).Itcan be attributedadditionallyto the task of improving the organization of the functioning of the equipment of electric centrifugal pumps (when optimizing the modes of its automatic restart, when switching on again or starting in maximum depression mode).In addition, it is very importantconducting studies of hydrodynamic processes in operated intelligentwells, organizing the functioning of channel for transmitting the geophysical data to the surface of earth (for example, monitoring temperature indicators, vibration of the body of the working submersible electric motor, oil pressure, etc.).
From the requirements listed above, it is obvious that for the implementation of modern intelligent well system, high-temperature electronics should be used -microprocessors with built-in sensors and detectors, as well as microcontrollers of network and system types.The implementation of intelligent electronic systems requires the creation of separate memory chips.The increase of temperature gradient in the oil-and-gas wells reaches the value of 25 °C when immersion into one kilometer deep into the earth.This means that when average temperature of the earth's surface is more than 0 °C,andonthe depth, for example, of 7 km, ambient temperature in the well may exceed +175 °C.It is far from limit, since experimental development of minerals (including oil and gas) is currently being carried out at extremely deep depths, in the wells where temperature reaches values more than +200 °C (at the depth more than 8 km), and the pressure is more than 25 kP/inch.However, today the depths exceed 10 km.
Figure 2 shows the corpus of electronic device used for conducting telemetry operations when drillingwells of similar depth.In the scientific literature, ultra-deep wells of high temperatures and pressure areclassified into three classes: 1) from +150 to +205 °C, 2) from +205 to +260 °C, and 3) above +260 °C [19].High-temperature electronic devices are designed to solve the urgent problem of import substitution, while ensuring proper quality and minimizing the cost of equipment.Each of set electronically controlled gate valves located near the perforations of electronic components corpus installed in the drilling rig is equipped with sensors and detectors that are monitoring the correct position of the gate valve of the drilling rig, temperature and pressure.The price of one foreign-made gate valve is approaching $500,000.

High-temperature electronic components for the aerospace industry
In addition to oil-and-gas industry, integrated microcircuits designed for high-temperature operation are relevant in aviation electronics (avionics) and astronautics [20].In the modern projects of MoreElectronicAircraft program (MEA), preference is given not to central onboard computer, but to variety of distributed components -microcontrollers and microprocessors.This makes it possible to reduce the number and length of copper cables, reduce their weight and increase reliability of aircraft piloting, bringing electronics closer to all executive mechanism (actuators).Such replacement minimizes the number of socketsandconnections leading to equipment failures, and align the aircraft control system with standard MIL-HDBK-217F [21].
At the same time, the technical solution associated with architecture approximation of distributed microcontrollers and microprocessors to aircraft engines leads to the fact that temperature range in which the devices operate takes from -55 to +200 °C.Use of forcing compulsory cooling in such systems can only complicate the problems, since it entails the significant increase in both the weight and cost of the aircraft.Potential breakdown of the cooling system can provoke failure of entire control system, which will make catastrophe inevitable.In addition, MEA program involves the control systems replacing of hydraulic type on the systems of electronic type, which increases their fault tolerance and reliability while reducing cost.
When implementing such mechatronics, it is required to use detectors, probes, sensorbased interfaces, data processing systems located near executive mechanisms (actuators) and operating in the high temperature range, and are themselves sources of increased heat.The application of high-temperature microcircuits (microchips) is also necessary in automotive electronics.As in aviation industry, the automotive branch (and, in general, entire transportbranch) of industry is moving to replace the control systems of hydraulic and mechanical type onthecontrol systems of electronic type.Their use accelerates significantly and facilitates both the production processes of the aircraft and the testing of the operability of all electronic systems of the vehicle, which reduces the cost, simplifies management and increases the reliability of its operation.
The same processes as in aircraft construction occur with production of electric vehicles, hybrid cars and unmanned vehicles, in which electric motors are controlled by electronic control systems.However, most science-intensive direction of high-temperature electronics is rocket-and-space direction, due to high requirements for radiation resistance and reliability.Each satellite manufactured for scientific or military research is unique in its own way, and for each experiment, it is required to create its own computing system.Specific features of rocket-and-space field do not allow the use of foreign microcircuits to create automated control systems.The seriality of required import-substituting devices is relatively low, and the microchips themselves must function successfully, under the influence of radiation, in the high-temperature range, for many years.Outer space can create significant difficulties in solving the problem of heat removal.Currently, planned space flights to earth orbit to near and far space require solving the tasks of increasing reliability and enhancement the temperature range of electronic equipment of new generation.

Requirements for components of rocket-and-space electronics
The trouble-free functioning and operation of microelectronics devices in space conditions puts forward strict requirements for their parameters.They are: in terms of durability of functioning and operation -not less than 200 thousand hours; in terms of resistance to the effects of accumulated radiation dose -not less than 200 kRad.In terms of resistance to the effects of heavy charged particles with linear type energy transfer -not less than 100 MeV × cm 2 /mg; to preserve all characteristics affecting performance after 50 ns of pulsed irradiation -up to 10 12 rad/s; in terms of resistance to the effects of neutrino flow -up to 10 13 neutrinos / cm 2 .
The sensitivity of the device to failures and malfunctions in the functioning of the equipment caused by effects of influence of cosmic particles with high-energy potential should be minimized.There is no doubt that there is urgent need to develop specialized series of integrated microcircuits designed for the application in the space.The expediency of creating electronic devices with similar characteristics is confirmed by the practical experience of foreign firms (Aeroflex, Atmel, etc.), which puts forward the new task of import substitution for domestic Russian developers.
For example, to build onboard control systems for spacecraft, microprocessors from the Aeroflex company (with characteristics: 66 MHz, with manufacturing technology -0.25 microns, containing 5 million transistors) and Atmel company (with characteristics: 100 MHz, with manufacturing technology 0.18 microns, containing 8 million transistors) are applicated.
Both types of microprocessors have the level of resistance to accumulated radiation dose of 300kRad, the threshold of resistance to failures of 10-15 MeV, and the level of resistance to the "snap (latch) effect" of 100 MeV × cm 2 / mg.To increase the level of resistance of microprocessors to various effects of single failures, the special solutions of circuit engineering were used for functional elements.To protect the calculation process from errors, in processors was used the majoring(the method for estimating the error weight, which consists in the process of determining the importance of errors in the program code).
In the future (5-10 years), the companies plan to produce the microprocessors with clock frequency of 150-200 MHz, and the number of transistors exceeding 10 million.Parity in the exploration of Russian outer space is possible only with the use in the space industry of element base of the same level.
Requirements for temperature range differ significantly depending on device locationthe place in spacecraft where equipment is located.In the modern scientific world, it is accepted generally to use five temperature ranges for integrated circuits.1) commercialfrom 0 to +70 °C; 2) industrial -from -40 to +85 °C; 3) aviation -from -40 to +125 °C; 4) military, of MIL-STD-883 standard, and 5) space -from -60 °C (for Russia) to +150 °C.The high-temperature range is highlighted particularly for microcircuits operating at ambient temperatures above +150 ° C.Not all complex physical devices, such as detectors and sensors used for space exploration, are designed to operate in the high-temperature range, but requirements for electronic components installed near such devices are similar.In most cases, requirements for them belong to military and space categories, and relate to electronics of spacecraft (satellites) located in high orbits, and/or operating in near and far outer space.
One of the most urgent problems facing domestic developers today is the development of electronic components for the spacecraft engine control system and equipment control during space flights to both near and far space.As in aviation, the application of distributed microcontrollers and microprocessors variety will reduce significantly the number and length of copper cables, reduce the weight of the spacecraft and increase the reliability of the automated control system.
It should be noted that the operating temperature of integrated microcircuits in orbit and in the near-space conditions varies from -250 °C to +200 °C, and all terrestrial satellites are built under such temperatures.Similar temperature range is observed due to the location of spacecraft: in Earth shadow or on its solar part.The average cosmic temperature of deep space, far from any stars, is near absolute zero: -270 °C.Thus, for space applications, it is necessary to develop import-substituting radiation-resistant electronic element base of wide temperature range.
3 Discussion about of characteristics 3.1 Characteristics of basic microcircuits.
Table 1 shows the main characteristics of microprocessors [21] of radiation-resistant application.To create multiprocessor systems, the microcircuits use SpaceWire and RapidIO standards, which have different data transfer rates.The standards complement each other.
SpaceWire channels are, in fact, the standard for space applications, with data transfer rate of up to 200 MB/s.In the RapidIO channels, the data transfer rate reaches 6.25 Gbit/s per line [22].The characteristics of microcircuits for the control systems are shown below.

System on crystal
System on crystal (SoC) 1907VM038 is considered integrated microchip prospective and promising for the systems development for airborne aviation and rocket-and-space applications.SoI is manufactured using "silicon-on-insulator" 0.25 microns technology.Figure 3 shows its structural and functional schemes.SoC consists of:32-bit control core CPU;128-bit arithmetic operations coprocessor (in Figure 3 -CP2);system controller with built-in DDR2 and SPI interfaces;2 Serial RapidIO channels; 4 SpaceWire;I2C and GPIO channels; and 2 controllers UART.Clock frequency is 100 MHz, RAM bandwidth is512 Mbytes/s.Design includes corpus of dumpled BGA type with 675 outputs made of metal ceramics.

Switchboard of serial channels 1907KH018
Microcircuitperforms the function of organizing communication channels between switches and SoCs, by data transmission channels RapidIO with serial (consistent)interface.The switchboard (commutator) is considered theprospective and promising device for operation as part of being developed highly productive onboard space systems, made using the "silicon-on-insulator" (SOI) technology of 0.25 microns [23,24].
The switchboard contains six RapidIO ports of data transfer with serial interface.The environment of data transmission is LP-Serial 4X or 1X.On each communication line, the maximum rate of data transfer reaches 1.25 Gbit/s.Figure 4 demonstrates a block diagram of the device.Distinctive features of the switchboard (commutator): switching tables, separate for each port, the presence of monitoring control system of the productivity of works performed; built-in unit designed to the errors controlling and managingoffailures and malfunctions.The switchboard can connect up to 256 devices (for example, SoCs, inputoutput controllers, etc.) into the single system.For the on-board systems, such quantities and numbers of devices is quite enough.Individual switching tables are designed for flexible configuration of the route of passing data packets through the network.
The system controlling the productivity of work performedis designed to monitoring in the communication channel the current characteristics of the data flow, overloads tracking that occur in the network, and determining the locations of possible blockages.Finding the intensity value in the data flow channel is carried out at the stage of choosing the network topology, during simulation modeling and analysis of experimental data.The cause of occurrence the congestion in the network may be the deterioration of the state of channel condition that has arisen as the result of failures.
Advance notification of occurring errors minimize the connection time of backup route.When choosing an alternative route (workaround) for data transmission, the switch microcircuit must determine which communication channels are blocked, and for what reason.
If all six ports are applicated in 4X regime (mode), the maximum value of power consumption does not exceed 6 Watts.Its decrease is provided in the regimes of operation of ports 1X, by means of gradual disconnection of transmitters, for each port individually.The microcircuit has two power channels: 2.5 V and 3.3 V. Its design assumes the presence of ceramic corpus (body), such as dumpled BGA, with 399 outputs.The special set of additional security measures provides increased resistance to hardware failures, which, when accessing the buffer memory device with data packets, includes the noise-resistant coding; the application of backup routing tables; the use of library elements for topological and solutions of circuit engineering.The switchboard microcircuit, which has advanced capabilities for conducting of diagnostic analysis of its operability, provides access to the status of diagnostic registers by way of the I2C interface.When receiving information from the integrated system about possible failures and errors, it is possible to output the discrete signals to the port, for their analysis with the support of the serviceability control system (SCS).Optimization of SCS system leads to increase in the reliability parameters of its operation as whole.

Multiport switchboard
Multiport switchboard (commutator) SpaceWire is microcircuit with built-in microprocessor, made using "silicon-on-insulator" technology (SoI) of 0.24 microns, is shown in the Figure 5.The clock frequency of multiport switchboard is 100 MHz, the power consumption 6 Watts maximally.Regimes of disconnection of currently unused functional blocks make it possible to reduce the power consumption of microcircuit.Relatively small number of elements is required for the device to work properly when performing the functions of switch.For example, external RAM microcircuitscan be disabled if necessary [23][24][25].
In order to prove the possibility of using the considered devices in rocket-and-space technology, the experimental investigations were carried out, in which the characteristics of important threshold values of linear energy losses of heavy charged particles (HCP) were measured.In thyristor effect, they do not exceed 80 MeV × cm 2 /mg; for single events, not more 6 MeV × cm 2 /mg.Under the influence of HCP, the cross-section of saturation by single events does not exceed 3×10 -8 cm 2 /bit; the value of the resistance level to the accumulated radiation dose is within 500 kRad.
High values of resistance can be explained by creation of new technological process for the production of microcircuits with the standards "silicon-on-insulator" (SoI) 0.25-0.35microns, as well as the development of special radiation-resistant electronics components.The temperature range for the stable operation of described above microcircuits is from -60 to +125 °C.So, these devices help to solve many problems that arise during the development of space control systems.
To understand the potential of using the described microcircuits in the high-temperature devices, the full-scale experimental investigations of described microcircuits were carried out at operating temperature +150 °C.At high temperatures,the frequency of operation decreases by 10% on average, and power consumption increases slightly, which indicates of safety margin in design and manufacturing technology.Duration of stable operation of devices in such high-temperature mode does not change [26][27].
In order to develop the full-fledged technological process for the production of microcircuits operating in the high-temperature range, its complete modernization is necessary: replacement of the impurity type, transition to combined (aluminum with wolfram, or tungsten) or wolfram specially designed conductors, increase in their crosssectional area, etc.Nevertheless, the principal possibility of import-substituting hightemperature microcircuits creating for use in the rocket-and-space field based on domestic projects is demonstrated very convincingly.To reduce the power consumed by the microcircuits and increase their reliability indicators, it is necessary to implement the data transmission environment as hierarchical environment.
At the same time, at the top level of the hierarchy is switched environment RapidIOwith rate of `data exchange up to 1 Gb/s per channel.At the lower level of the hierarchy, there is switched environment SpaceWire with rate of data exchange up to 200 Mbit/s.At the lowest level, there are multiplex communication channels with low speeds, made according to GOST P 52070-2003 and RS232/RS485.The conducted investigations and natural experiments have shown the fundamental possibility of manufacturing of high-temperature microcircuits during the modernization of technological process, as well as modification of already developed domestic projects for achievement the operating temperatures of the microcircuits functioning of the order of +200 °C or more.

Fig. 1 . 2 .
Fig. 1.The process of wells drilling Fig. 2. Corpus of electronic components, installed in the drilling rig

Table 1 .
Comparison of characteristics of radiation-resistant microprocessors