Radiation testing of semiconductor devices for space electronics

Radiation effects testing, part selection, and hardness assurance for application to electronic components in the natural space environment are discussed. The emphasis is on semiconductor devices, primarily silicon microcircuits, which are used in the greatest quantity and which, in most cases, are the most sensitive. After a summary of the natural space radiation environment and the effects of radiation on semiconductor devices, laboratory simulation of space radiation and extrapolation to space are covered. Radiation testing is performed to understand failure mechanisms, to characterize the radiation response of specific devices, and to provide data for lot acceptance. Part selection and hardness assurance are discussed by contrasting the traditional approach with the unique aspects of space systems. Some recommendations are made for treating the more complex aspects of space system microcircuit hardness assurance     

Reliability of semiconductor devices for submarine-cable systems

The Bell System initiated development of semiconductor devices for use in broad-band repeatered coaxial submarine-cable telephone systems in the early 1960's. Development of such devices has continued at varying levels of activity to this date. Now, over a decade later, more than five years of successful operational life have elapsed on the first installed system; one transatlantic system is in operation and several more of equal or greater length are in various stages of construction. Laboratory-like life validation tests have been conducted on all the devices for use in these systems, and up to seven years of history have elapsed on groups of 100 devices representative of the five varieties used in the first system. No failures have been observed either in service or in life validation tests, thereby confirming a FIT rate of better than five. Moreover, variables data for the representative samples aged for seven years indicate that the confirmed FIT rate may be extremely conservative. Silicon diodes aged below breakdown are more stable than the life-test system designed to evaluate their reliability. Silicon diodes aged in breakdown show a linear drift in leakage current which is so small that it is not detectable except with an ultrasensitive test system. Germanium transistors evaluated over this same period show that the change in current gain they exhibit will be substantially less than the goal established for them at the inception of development. Silicon transistors being developed for a new higher capacity system show promise of exceeding the stability of the more extensively evaluated germanium devices. These results have broader implications than their relevance to submarine-cable system performance since they indicate that the reliability which has long been considered to be inherent in semiconductor devices not only has been demonstrably achieved in quantitative terms but can be considered to be designable for future system applications.     

Optimized cooling systems for high-power semiconductor devices

Straightforward air cooling of semiconductor devices has gradually been replaced by methods using liquid coolants, especially water cooling. In this paper, more advanced cooling devices for hockey-puck-type and module-type semiconductors are suggested. An established heat sink made of aluminum nitride for the water cooling of hockey-puck-type semiconductors has been used as a basis for the development of high-performance heat sinks for increased heat flux densities. By means of thermal and fluid dynamics simulation tools the internal geometry has been optimized with regard to improved heat transfer and reduced pressure drop. The simulation results have been confirmed by a number of experiments using various measuring techniques. As an alternative cooling method for semiconductor modules, a modified baseplate comprising a number of fins for direct water cooling has been suggested. For an intelligent temperature management control algorithms have been developed, resulting in a prototype application-specific integrated circuit which has been implemented for test purposes     

Reliability of new semiconductor devices for long-distance opticalsubmarine-cable systems

Results from reliability tests conducted on three types of semiconductor devices used in optical repeaters are reported. The devices tested are: two types of 1.3-μm-band InGaAsP/InP laser diodes: a Ge avalanche photodiode; and monolithic integrated circuits. The devices have proved to be suitable for use in a long-distance optical submarine-cable system, such as the third transpacific cable system     

Potential impact of emerging semiconductor technologies on advancedpower electronic systems

It is shown that a simple expression for k_D= R_on×C_in of a power semiconductor device can be used to evaluate the optimum performance feasible from a given material technology. A high-density, high-frequency microelectronic power supply based on synchronous rectifier switching topology is used to illustrate the potential impact of emerging semiconductor technologies on advanced power electronic systems. It is shown that optimum power devices based on wide-energy-bandgap semiconductors such as silicon carbide and diamond provide the basis for power conversion at very high frequencies     

Ion-implanted semiconductor devices

Ion implantation is finding increased usage in device fabrication owing to precise control and reproducibility of the charge and depth distribution of the implanted-dopant profile. The MOST illustrates the application of charge control through threshold-voltage adjustment and though predepostion for drive-in diffusion to form complementary devices. A compilation of range-energy data for B, P, and As in silicon is given along with factors which influence the implanted-dopant distributions after anneal treatments. Implantation procedures are presented for high-frequency bipolar transistors which depend critically on both charge and depth control of the emitter and base profiles. Another important aspect of ion implantation is lateral control, a feature which is necessary for high packing density circuits. Disorder effects associated with implantation through oxide masks are discussed. A brief account of implantation for GaAs devices is also included.     

Power semiconductor devices: an overview

Advances in power semiconductor devices are discussed, focusing on the adaptation of silicon integrated circuit wafer processing methods to the design and fabrication of power devices. Some basic properties of power devices are reviewed, along with recent adaptations of wafer processing technology. Two trends are discerned: increasing use of self-aligned, double diffused MOS gate structures to achieve devices with low-current drive requirements; and movement toward an ideal one-dimensional device, thereby making more efficient use of the available area. Different devices are compared. Techniques that have potential for use in power device are discussed: use of trenches, direct wafer bonding, cellular bipolar transistors, and junction termination. The combination of power switches with control logic on the same chip is briefly considered     

Nonvolatile semiconductor memory devices

An attempt is made to survey and assess the nonvolatile semiconductor memory devices including charge-storage devices and FET's with ferroelectric gate insulators. The charge-storage devices are further divided into two groups: 1) charges-trapping devices such as the MNOS and the MAOS, and 2) floating-gate devices such as the FAMOS and the DDC. Approaches for achieving virtual nonvolatility in otherwise volatile semiconductor memories are briefly disscused. Novel structures which provide nonvolatility as well as the theoretical limit of memory array density are also explored.     

Progress in silicon carbide semiconductor electronics technology

Silicon carbide’s demonstrated ability to function under extreme high-temperature, high-power, and/or high-radiation conditions is expected to enable significant enhancements to a far-ranging variety of applications and systems. However, improvements in crystal growth and device fabrication processes are needed before SiC-based devices and circuits can be scaled-up and incorporated into electronic systems. This paper surveys the present status of SiC-based semiconductor electronics and identifies areas where technological maturation is needed. The prospects for resolving these obstacles are discussed. Recent achievements include the monolithic realization of SiC integrated circuit operational amplifiers and digital logic circuits, as well as significant improvements to epitaxial and bulk crystal growth processes that impact the viability of this rapidly emerging technology.     

Electron bombarded semiconductor devices

The first electron bombarded semiconductor (EBS) devices have recently appeared on the market. These devices have already demonstrated that EBS has considerable promise as an important new electron device for power amplification and control. EBS devices are described with particular emphasis on power devices. The basic EBS principle, some of the analysis used in device design, general considerations in designing the various elements of the device, overall device design, semiconductor processing, and reliability considerations are discussed. Predictions of general directions for future work are made. Some historical information is also presented as well as a brief comparison with other competing power devices.     

Active semiconductor microdisk devices

The design of active semiconductor microdisk switches, modulators, or wavelength routers enabled by modulating the transfer characteristics of a resonant cavity is investigated. A simple theoretical model based on coupled-mode theory is used to elucidate design trends and constraints in the cases where electroabsorption, gain, and free carrier injection are employed to modulate the resonator characteristic     

Single nanoparticle semiconductor devices

Using a new technique in forming the cubic single-crystal silicon nanoparticles that are about 40 nm on a side, the authors have demonstrated a vertical-flow surround-gate Schottky-barrier transistor. This approach allows the use of well-known approaches to surface passivation and contact formation within the context of deposited single-crystal materials for device applications. It opens the door to the novel three-dimensional integrated circuits and new approaches to hyper integration. The fabrication process involves successive deposition and planarization and does not require nonoptical lithography. Device characteristics show reasonable turn-off characteristics and on-current densities of more than 10/sup 7/ A/cm/sup 2/.     

III-V compound semiconductor devices: Optical detectors

This article presents a review of the historical developments in optical detectors and discusses the motivations for interest in III-V semiconductors for optical-detector applications. Early device work in both depletion-mode photodiodes and avalanche photodiodes in III-V semiconductors is covered as well as the improvements that have been made in avalanche photodiode structures through work in silicon. Also, the results of ionization coefficient measurements on III-V compounds are summarized. Finally, several examples of recent avalanche photodiodes that utlilize the unique properties of heterostructures are presented.     

Electrostatic discharge in semiconductor devices: protectiontechniques

Electrostatic discharges (ESDs) are everywhere-in our homes and businesses. Even the manufacturers of the electronics experience ESD failures in their factories. Electronic devices are sensitive to ESD. ESD results in failure of our computers, calculators, and car phones. There are ways to protect these sensitive components. This paper looks at ESD protection from a two-pronged approach: reducing the likelihood of having an ESD event and improving the robustness of the devices themselves. The first approach focuses on reducing the amount of charge that is developed and controlling the redistribution of any charges that are developed The second approach reviews ways to improve the circuit robustness by improving individual circuit elements and by adding additional elements for charge flow control and voltage clamping     

Molecular electronics: from devices and interconnect to circuits and architecture

As the dominating CMOS technology is fast approaching a "brick wall," new opportunities arise for competing solutions. Nanoelectronics has achieved several breakthroughs lately and promises to overcome many of the limitations intrinsic to current semiconductor approaches. Most of the results in this area reported until now focus on devices and interconnect; this work goes several steps further and presents issues related to circuits and architecture. Based on proposed nanoscale interconnect and device structures, we explore the design space available to the nanoelectronic circuit designer and system architect.     

Bulk negative-resistance semiconductor devices

Recent research on semiconductors that exhibit bulk negative resistivity has led to new devices for pulse regeneration, logic function generation, amplification, and millimeter-wave power generation. These are bulk devices in the sense that ac gain is derived from the bulk negative-resistance property of certain uniform semiconductors, rather than from the properties of junctions between different types of semiconductors. Bulk devices are capable of operating with more power at higher speeds and frequencies than conventional junction devices such as transistors.