Microwave mixer and detector diodes

Recent advances in microwave mixer and detector diodes are reviewed. Devices considered are germanium back diodes, silicon and gallium arsenide point-contact diodes, and Schottky-barrier diodes. Current work on low-barrier (n-type) Schottky diodes and high-burnout point-contact diodes is also described. Experimental results of CW and RF pulse burnout of these devices are summarized. Different approaches to improve the power-handling capability of Schottky diodes at S-, X-, and Ku-band frequencies are considered.     

Low-Noise Properties of Microwave Backward Diodes

This paper describes, for what is believed to be the first time, the low-noise properties of backward tunnel diodes in microwave applications. The physics of the diodes are reviewed together with some of the characteristics and equivalent circuit parameters. The diodes are then considered as mixer diodes with IF in the audio range and also the standard 30-Mc IF. Another promising application considered is the use of the backward diodes in low-level detection. The results show that the noise figure at 13.5 kMc with a 1-kc IF is around 15 db better than any commercially available mixer diodes. Using 30-Mc IF, the noise figure of backward diode mixers is without special optimum design, comparable to the best mixer diodes on the market. Of great importance, especially in micro-miniaturization, is the fact that these diodes may be used with a very low local oscillator power (50 µw or less). The high nonlinearity of the I-V characteristic at the origin and the low 1/f noise properties of these diodes are also of benefit in crystal video receivers and other low-level detector applications.     

Backward Diodes for Low-level Millimeter-Wave Detection

Backward diodes (low peak current tunnel diodes) suitable for small-signal detection applications in the millimeter-wave region have been fabricated from n-type germanium. The diodes have the dimensions and geometry of point-contact diodes. For millimeter-wave signal levels below about - 20 dbm, the current sensitivity of these units is an order of magnitude greater than that of selected existing diodes for this frequency range. When employed as millimeter-wave frequency converters, the minimum conversion loss is comparable to that of conventional diodes, but the beating oscillator power requirements may be somewhat reduced. The diode noise factor at megacycle IF frequencies is comparable to that of conventional units, and in the low audio IF range it is expected to be markedly decreased. The fabrication of these diodes is described and their initial performance at selected frequencies from 11 Gc to 300 Gc is discussed.     

A comparison of silicon and gallium arsenide large signal IMPATT diode behaviour between 10 and 100 GHz

A large-signal computer simulation of an IMPATT diode has been used to investigate the differences between gallium arsenide and silicon IMPATT diodes. The variations of efficiency with frequency, current density, series resistance, amount of punch-through and reverse saturation currents are all investigated.With no ‘parasitic’ effects the silicon diode efficiency remains almost constant between 10 and 100 GHz, whereas the efficiency of gallium arsenide diodes is higher than that of silicon diodes at 10 GHz but decreases to the silicon diode efficiency at 100 GHz. A lower residual avalanche particle current in gallium arsenide diodes results in a higher susceptibility to reverse saturation currents. In silicon diodes the higher material resistivity affects the efficiency more than in gallium arsenide diodes, the removal of series resistance by having a punched-through diode does not necessarily increase the efficiency. The difference between experimental results quoted in the literature and the theoretical calculations are considered in terms of these effects. By considering the differences in ionization coefficients and velocities between the materials the lower efficiency of silicon diodes compared to gallium arsenide diodes is explained, also the lower breakdown voltage of gallium arsenide diodes compared to silicon diodes of the same frequency, and the ‘forward-bias’ effect found at high frequencies in gallium arsenide diodes.     

Minority carrier MIS tunnel diodes and their application to electron- and photo-voltaic energy conversion—II. Experiment

The theory of metal-insulator-semiconductor (MIS) tunnel diodes has been described in a companion paper for the case where the insulating layer is so thin that large tunnel currents can flow between the metal and the semiconductor. Of particular interest was the case where the dominant component of tunnel current is between the metal and the minority carrier energy band in the semiconductor (minority carrier diodes). In the present paper, these diodes are investigated experimentally. The differences between minority and majority carrier diodes are demonstrated. Minority carrier diodes are shown to possess properties similar to p-n junction diodes as predicted theoretically. The effectsof different metal contacts, insulator thicknesses, and substrate resistivities are investigated and confirm previous theory. The application of the minority carrier MIS tunnel diodes to energy conversion employing the electron-voltaic effect is investigated experimentally. The diodes were found to be more efficient in this application than p-n junction diodes. Other possible applications of the diodes are as photo-voltaic energy converters, as injecting contacts, and as photo-diodes or elements of photo-diode arrays.     

碳化硅MPS:新一代功率开关二极管

碳化硅MPS(Merged PiN Schottky diode)具有很好的开关特性，并具有PiN二极管高阻断电压、低漏电流和SBD小开启电压，大导通电流以及高开关速度的优点，是最有希望的新一代功率开关二极管。文章系统地介绍了碳化硅MPS的结构和性能。理论和实验分析表明，碳化硅材料的优异性能与MPS结构的优势相结合，是当今功率开关管发展的趋势。     

Millimeter-wave point-contact and junction diodes

Millimeter-wave "point-contact" diodes are classed as conventional point-contact diodes (and modifications on them), which depend primarily upon a point-contact metal-semiconductor junction for their rectification properties; or as junction diodes with point-contact geometry, which are small-area millimeter-wave adaptations of the p-n junction diodes, normally made for use at lower frequencies by alloying, diffusion and other techniques. In a general way, techniques used in the fabrication of these various diodes are described; then the uses to which they have been put is detailed, and the best reported performance characteristics in various millimeter-wave applications are compared. Emphasis is put on demonstrated performance, but highly experimental and tentative laboratory results are freely quoted. Included are discussions of 1) conventional point-contact diodes of various semiconductors; 2) diodes having point-contact geometry but exhibiting electrical properties approximating those of alloyed and diffused p-n junctions, diodes made by planar techniques, a "thermoelectric effect hot carrier" diode, point-contact photodetectors and photoemitters; and 3) a millimeter-wave avalanche transit-time oscillator diode. The use of these diodes as millimeter-wave detectors, amplifiers, oscillators, harmonic generators, and modulators is considered.     

一种新型渐变掺杂理想欧姆接触SiGeC/Si功率二极管

将新器件结构与新型半导体材料相结合,提出了一种新型的n-区三层渐变掺杂理想欧姆接触型p (SiGeC)-n-n 异质结功率二极管,并对n-区的杂质分布梯度进行了优化.基于MEDICI,给出了该结构的关键物理参数模型,并在此基础上对新结构的设计思路和工作原理进行了全面分析.结果表明,与常规理想欧姆接触结构相比,该新结构在保持快而软反向恢复特性的前提下,反向阻断电压增加了近一倍,而且正向通态特性也有所改善,很好地实现了功率二极管中Qs-Vf-Ir三者的良好折中.     

GaN基和GaAs基半导体激光器的电学特性研究

介绍了一种能够全面表征半导体二极管器件的电学特性的方法,此方法结合半导体二极管的正向交流特性和直流特性,称之为正向交流小信号法。利用该方法深入地研究和对比分析了GaN基和GaAs基半导体激光器的电学特性,包括表观电容、串联电阻和理想因子。实验结果表明,对于GaN基和GaAs基半导体激光器,其开始发光的过程同步于其电容由正转变为负的过程。进一步实验结果表明,GaN基半导体激光器比GaAs基半导体激光器具有更大的串联电阻和更大的理想因子。这是由于GaN基激光器的器件工艺不够完善以及外延生长的GaN材料具有很大的位错密度。该研究为提高和改善GaN基激光器的性能提供了必要的依据以及理论指导。     

一种新型渐变掺杂理想欧姆接触SiGeC/Si功率二极管

将新器件结构与新型半导体材料相结合,提出了一种新型的n-区三层渐变掺杂理想欧姆接触型p+(SiGeC)-n-n+异质结功率二极管,并对n-区的杂质分布梯度进行了优化.基于MEDICI,给出了该结构的关键物理参数模型,并在此基础上对新结构的设计思路和工作原理进行了全面分析.结果表明,与常规理想欧姆接触结构相比,该新结构在保持快而软反向恢复特性的前提下,反向阻断电压增加了近一倍,而且正向通态特性也有所改善,很好地实现了功率二极管中Qs-Vf-Ir三者的良好折中.     

新型双区阴极结构体效应二极管

常规的GaAs体效应二极管的阴极结构多采用欧姆阴极,在毫米波频段(W 波段),器件的转换效率小于1%.介绍了一种新型的双区阴极结构在W 波段体效应二极管中的实现,并研制出了样品器件.采用此种结构,可以显著提高毫米波器件的输出功率和转换效率.     

Mass-production-type GaAs IMPATT diodes in s.h.f. band

The structure of mass-production-type GaAs IMPATT diodes is described. By making the diodes with a mesa structure embeded in polyimide resin, batch fabrication of small-area diodes has become possible over a large wafer area. Diodes so far obtained have almost the same characteristics as those of conventional GaAs IMPATT diodes.     

Bipolar Conduction Impact on Electrical Characteristics and Reliability of 1.2- and 3.5-kV 4H-SiC JBS Diodes

4H-SiC Junction Barrier Schottky (JBS) diodes (1.2 and 3.5 kV) have been processed using the same technology with two different layouts. From 4 A and for the whole temperature range, the 3.5-kV diodes exhibit a bipolar conduction independent of the layout. However, the behavior of the 1.2-kV diodes depends on the design. At 500 V–300 $^{circ}hbox{C}$, the leakage current is only 100 nA and 10 $muhbox{A}$ for the 3.5- and 1.2-kV diodes, respectively. The switch-off performances show a reverse peak current of only 50% of the nominal current at 300 $^{circ}hbox{C}$ for all JBS diodes. The JBS diodes have a surge current capability of around 80 A, two times higher than the Schottky diodes. DC electrical stresses are performed during 50 h, and all the 1.2-kV diodes exhibit no bipolar degradation. Nevertheless, some slight bipolar degradation is observed in 3.5-kV JBS diodes. Electroluminescence measurements exhibit the expansion of stacking faults in 3.5-kV diodes unlike in 1.2-kV diodes.      

Electrical properties of bulk-barrier diodes

Like Schottky-barrier diodes, bulk-barrier diodes (BBD's) are majority-carrier devices and can, therefore, be used up to very high frequencies. In both types of diodes, charge-carrier transportation is determined by an energy barrier. In Schottky-barrier diodes the barrier is located at the metal/semiconductor boundary, whereas in BBD's it is found inside the semiconductor and is the result of a space-charge zone in a three-layered n-p-n or p-n-p structure with a very thin base region. The height of the barrier is determined by technological parameters such as doping density and layer thickness. As the current in BBD's, just as in Schottky-barrier diodes, is an exponential function of barrier height, the current-voltage characteristic can be adjusted by technological means.     

Comparison of metal-n-p+ and p+ BARITT small-signal noise measures

p+-n-p+ BARITT diodes offer optimum noise measures of approximately 9 dB. A small-signal computer simulation is used to compare the noise measures of p+-n-p+ and metal-n-p+ (m-n-p+ diodes. For the range of operating conditions studied, the noise measures of the m-n-p+ diodes are consistently greater than the corresponding noise measures of the p+-n-p+ diodes.     

Physical parameters extraction from current–voltage characteristic for diodes using multiple nonlinear regression analysis

In this work, the two-step iteration combined with the nonlinear multiple regression technique to extract physical parameters for diodes, using a simple physical-based current–voltage (I–V) model is demonstrated. This statistical method can be applied for sampling for a wide variety of diodes including light-emitting diodes (LEDs) and Schottky diodes. Our results show the technique is an accurate and systematic approach for extracting diode parameters. The calculated recombination currents indicate the recombination efficiency for LEDs and the quality for Schottky diodes.     

Low-frequency noise behaviour of high-energy electron irradiated Sin+p junction diodes

The low-frequency noise behaviour in forward operation of high-energy electron irradiated Si n⁺p diodes is reported. For diodes fabricated on Czochralski substrates, negligible change in noise is observed, whereas for float-zone diodes, a reduction occurs after the irradiation. By comparison with reverse bias gated diode characteristics. It is concluded that the excess 1/f noise of the irradiated diodes is not correlated with the irradiation-induced degradation of the Si-SiO₂ interface     

Thermally accelerated life testing of single mode, double-heterostructure, AlGaAs laser diodes operated pulsed at 50mW peak power

Single spatial mode, double-heterostructure, channel-substrate-planar AlGaAs laser diodes have been life tested under thermally accelerated conditions to characterize the reliability of the diodes in a digital, optical communication system intended for space application. The diodes were operated pulsed under constant drive current conditions at 50 mW peak power, 25 ns pulse width, and 1 percent duty cycle in a dry, inert environment at ambient test temperatures at 40,55, and 70°C. Diode performance parameters as related to the space application, such as pulsewidth, peak power, wavelength spectrum, spatial mode, and threshold current, were periodically monitored. Tests have continued for over 14 000 h. The test results for all diodes with failure defined by power degradation alone is compared to the test results for single mode diodes with failure defined by power degradation, wavelength shift and spatial mode changes. It is found that the life test results are substantially equivalent but differ from earlier published reports for laser diodes operated CW. An activation energy of about 0.39 eV is deduced with a predicted median life of about5 times 10^{4}h at 20 °C. These values are somewhat lower than those found for diodes operated CW and are attributed to the use of single mode laser diodes here. It is concluded that thermally accelerated life testing for single spatial mode laser diodes must incorporate a means to separate bulk material, current, and optical density induced degradation effects. A test scheme is proposed.     

Influence of active-layer width on the performance of homojunction and single-heterojunction GaAs light-emitting diodes

For epitaxial GaAs homojunction and single-heterojunction (s.h.) l.e.d.s, light power output and risetime as a function of active-layer width were investigated. Narrow-base homojunction diodes can be markedly faster than s.h. diodes, the rise time of which is limited by the electron lifetime. However, for equal width of the active layer and equal injection level, the light power output of s.h. diodes is superior, compared with that of homojunction diodes.     

The Use of Constant Current Diodes in Preventing Electrical Shock from Hospital Equipment

The use of constant current diodes in medical electronic equipment is discussed. Advantages of using the diodes instead of fuses include 1) instantaneous limiting of patient current to a safe value, and 2) the nonself-destructive operation of the diodes.