Silicon Diode Temperature Sensors Research Articles

Dependence of the accuracy of the silicon diode temperature sensors for cryogenic thermometry on the spread of their parameters

Experimental samples of silicon diode temperature sensors for cryogenic thermometry are prepared. The process spread and variability of these diode temperature sensors and their effect on the parameters of these diode temperature sensors are studied. In particular, it was found that the spread of the base region doping level in the samples did not exceed 20%, the thickness spread of the base region is 3.5%. The measurement accuracy is highly dependent on the ideality factor spread: at room temperature and when the operating current is 1 μA, 1% change in the value of the ideality factor leads to a measurement error of ± 0.35 °C and a change of 10% leads to a measurement error of ± 3.6 °C.

Cryogenic Diode Thermometer Insensitive Completely to Magnetic Fields Up to 1 T

The article presents investigation results concerning silicon p-n junction diodes with heightened diode base doping level up to a critical value for the insulator-metal transition. Accent is made on application of such the diodes as temperature sensors in cryogenic region and in the presence of magnetic fields, i.e. under conditions when available commercial silicon diode temperature sensors become inapplicable. The reason is a freezing-out of the free current carriers in their lightly doped bases. In this case the base conduction becomes hopping with large magnetoresistance, and an impact ionization of the frozen-out carriers in the electric field results in electrical instability (hysteretic phenomena in the current-voltage characteristics). It is shown that the diodes investigated are free of the electrical instabilities inherent in the commercial diodes, and can operate with much lower the sensor working currents. The lower the operating current, the smaller is the measurement error connected with magnetic-field influence. At the operating currents of 10 and 1 μA, the sensor proves to be insensitive completely to magnetic fields up to 1 T.

Development of diode temperature sensors with operating range up to 750 K

The problem of expansion of the range of functioning of diode thermosensors in the region of high temperatures is considered and some of the results of the author’s research in this area are given. To solve this problem, it is proposed to use diode structures based on wide bandgap semiconductor compounds in the III-V system. The technological method of producing prototypes of high-temperature diode temperature sensors based on GaP is developed. The presented method allows manufacturing samples of diode temperature sensors, the high-temperature limit of which exceeds the limit of functioning of commercial silicon diode temperature sensors by about 200–300 K. The experimental methods of obtaining epitaxial structures of solid solutions of AlGaAs and fabricating diode temperature sensors based on them are developed. It is shown that the approach chosen in this work allows extending the thermometric characteristics of such diodes in the high-temperature region by approximately 150–250 K. The paper presents the methodology for forming InGaN device structures and production of prototype high-temperature diode temperature sensors based on them. This technique with revisions can be used for the manufacture of diode temperature sensors and other devices for high-temperature applications, the entire range of solid solutions in the InN-GaN system. The parameters and characteristics of the obtained diode temperature sensors are investigated. The results of the research can be used by specialists in the field of electronics and optoelectronics in the development and production of semiconductor devices.

Large scale production of densified hydrogen to the triple point and below

Recent demonstration of advanced liquid hydrogen storage techniques using Integrated Refrigeration and Storage technology at NASA Kennedy Space Center led to the production of large quantities of densified liquid and slush hydrogen in a 125,000 L tank. Production of densified hydrogen was performed at three different liquid levels and LH2 temperatures were measured by twenty silicon diode temperature sensors. Overall densification performance of the system is explored, and solid mass fractions are calculated. Experimental data reveal hydrogen temperatures dropped well below the triple point during testing, and were continuing to trend downward prior to system shutdown. Sub-triple point temperatures were seen to evolve in a time dependent manner along the length of the horizontal, cylindrical vessel. The phenomenon, observed at two fill levels, is detailed herein. The implications of using IRAS for energy storage, propellant densification, and future cryofuel systems are discussed.

Modification of a liquid hydrogen tank for integrated refrigeration and storage

The modification and outfitting of a 125,000-liter liquid hydrogen tank was performed to provide integrated refrigeration and storage capability. These functions include zero boil-off, liquefaction, and densification and therefore require provisions for sub-atmospheric tank pressures within the vacuum-jacketed, multilayer insulated tank. The primary structural modification was to add stiffening rings inside the inner vessel. The internal stiffening rings were designed, built, and installed per the ASME Boiler and Pressure Vessel Code, Section VIII, to prevent collapse in the case of vacuum jacket failure in combination with sub-atmospheric pressure within the tank. For the integrated refrigeration loop, a modular, skeleton-type heat exchanger, with refrigerant temperature instrumentation, was constructed using the stiffening rings as supports. To support the system thermal performance testing, three custom temperature rakes were designed and installed along the 21-meter length of the tank, once again using rings as supports. The temperature rakes included a total of 20 silicon diode temperature sensors mounted both vertically and radially to map the bulk liquid temperature within the tank. The tank modifications were successful and the system is now operational for the research and development of integrated refrigeration technology.

On-Chip Sensing of Thermoelectric Thin Film's Merit.

Thermoelectric thin films have been widely explored for thermal-to-electrical energy conversion or solid-state cooling, because they can remove heat from integrated circuit (IC) chips or micro-electromechanical systems (MEMS) devices without involving any moving mechanical parts. In this paper, we report using silicon diode-based temperature sensors and specific thermoelectric devices to characterize the merit of thermoelectric thin films. The silicon diode temperature sensors and thermoelectric devices were fabricated using microfabrication techniques. Specifically, e-beam evaporation was used to grow the thermoelectric thin film of Sb2Te3 (100 nm thick). The Seebeck coefficient and the merit of the Sb2Te3 thin film were measured or determined. The fabrication of silicon diode temperature sensors and thermoelectric devices are compatible with the integrated circuit fabrication.

Smoothing cubic spline approximation of silicon diode temperature sensors thermometric characteristics

Smoothing cubic spline approximation of silicon diode temperature sensors thermometric characteristics

Radiation-resistant silicon diode temperature sensors

Abstract We present a new type of silicon diode temperature sensors (DTSs) with high radiation resistance up to the dose of gamma irradiation ∼107 rad. Investigations of electrophysical and metrological characteristics of DTSs have been carried out in the range of temperatures 220–350 K and currents 10−11 to 10−2 A under gamma irradiation that allowed to reveal operating regimes with minimal influence of radiation on the device thermometric characteristics. A theoretical analytical model for the DTSs with almost ideal carrier transport has been proposed to explain the experimental behaviour of transport differential characteristics (ideality factor m, differential resistance) under irradiation. The observed non-monotonical dependencies of the ideality factor m on the current I are described well by the influence of generation–recombination and drift current components to the diffusion current of the minority carriers. The occurrence of a minimum in the m(I)-dependencies is due to a competition of these additional currents. The characteristic lifetimes of the minority carriers in the base and in the space-charge region of the diode structure have been determined. The DTSs are advanced devices with high sensitivity, accuracy, reproducibility, and easily adaptive with electronic equipment when operating in long circuits in radiation environments.

Silicon diode temperature sensors for process systems

Thermocouples and platinum resistance thermometers are commonly employed in low temperature engineering and process cycles. This paper argues that temperature sensors based on silicon diodes provide superior performance, giving higher accuracy and fast response, with simpler instrumentation.

A portable meter for the assessment of human heat stress

An instrument has been developed which senses the factors in the environment which contribute to human heat stress and displays on a meter a composite heat stress index. This is the WBGT Index put forward by Yaglou et al. in 1956 defined as 0.7 (natural web bulb temperature)+0.2 (black 6 in globe temperature)+0.1 (dry bulb temperature). As was shown, it is possible to use a much smaller globe, eliminate the dry bulb sensor and still derive the same information as before. The result is a simplification which not only improves the speed of response but makes the instrument compact and easy to handle. Since the output of the silicon diode temperature sensors is linear with temperature, weighted summation can be effected by a simple resistive network. The electronics comprise chiefly two operational amplifiers. The taut-band meter has a hand calibrated scale and is protected against overload. Battery life is of the order of 700 h.