Potentials of GaP as millimeter wave IMPATT diode with reference to Si, GaAs and GaN

This paper presents the simulation results of DC,small-signal and noise properties of GaP based Double Drift Region( DDR) Impact Avalanche Transit Time( IMPATT) diodes. In simulation study we have considered the flat DDR structures of IMPATT diode based on GaP,GaAs,Si and GaN( wurtzite,wz) material. The diodes are designed to operate at the millimeter window frequencies of 94 GHz and 220 GHz. The simulation results of these diodes reveal GaP is a promising material for IMPATT applications based on DDR structure with high break down voltage( V_B) as compared to Si and GaAs IMPATTs. It is also encouraging to worth note GaP base IMPATT diode shows a better output power density of 4. 9 × 10~9 W/m~2 as compared to Si and GaAs based IMPATT diode. But IMPATT diode based on GaN( wz) displays large values of break down voltage,efficiency and power density as compared to Si,GaAs and GaP IMPATTs.     

8毫米硅连续波崩越二极管

叙述8毫米硅连续波崩越二极管的设计和制造,在频率35 GHz附近,金集成热沉的双漂移崩越管获得400～800mW连续输出功率,效率5％～10％,结温200～250℃。     

SiC/GaN IMPATT二极管的交流性能研究

利用p型宽带隙材料SiC替代p型GaN,制作了一种p-SiC/n-GaN异质结双漂移(DDR)IMPATT二极管.对器件的交流大信号输出特性进行数值模拟仿真.结果表明,相比传统GaN单漂移(SDR)IMAPTT二极管,p-SiC/n-GaN新结构DDR器件的击穿电压、最佳负电导、交流功率密度和直流-交流转换效率都获得了...     

Effect of optical illumination on DDR IMPATT diode at 36 GHz

A reverse biased p-n junction diode with proper resonant cavity and boundary conditions is able to generate rf power and shows normal DC and small signal properties designed with semiconductor materials like 4H-SiC, GaAs, InP, Si-based DDR IMPATT structure at Ka band with dark condition. But when it is exposed to optical illumination through a proper optical window for both top mounted (TM) and flip chip (FC) configuration, it shows the influence on the oscillator performances in that band of frequency. The simulated results are analyzed for 36 GHz window frequency in each of the diodes and relative differences are found in power output and frequency of all these diodes with variable intensities of illumination. Finally it is found that optical control has immense effect in both FC and TM mode regarding the reduction of output power and shifting of operating frequency from which optimization is done for the best optically sensitive material for IMPATT diode.     

Low noise wide bandgap SiC based IMPATT diodes at sub-millimeter wave frequencies and at high temperature

We have presented a comparative account of the high frequency prospective as well as noise behaviors of wide-bandgap 4H-SiC and 6H-SiC based on different structures of IMPATT diodes at sub-millimeter-wave frequencies up to 2.18 THz. The computer simulation study establishes the feasibility of the SiC based IMPATT diode as a high power density terahertz source. The most significant feature lies in the noise behavior of the SiC IMPATT diodes. It is noticed that the 6H-SiC DDR diode shows the least noise measure of 26.1 dB as compared to that of other structures. Further, it is noticed that the noise measure of the SiC IMPATT diode is less at a higher operating frequency compared to that at a lower operating frequency.     

A study of the power handling ability of gallium arsenide and silicon,single and double drift IMPATT diodes

The concept of a critical current density effect on the operation of silicon and gallium arsenide IMPATT diodes is examined using large signal analysis. This critical current density effect does not appear to exist in the form that is generally thought of to-date. However, other physical processes develop at high current densities which gradually degrade diode efficiencies. These processes are worse in silicon diodes than in gallium arsenide diodes because at a given frequency of operation silicon diodes need a lower doping density than gallium arsenide diodes due to the lower saturated drift velocities of carriers in gallium arsenide. Reasons are suggested which explain why these other processes develop before a true critical current density limit is seen. New scaling data for limits on power handling ability vs frequency of gallium arsenide IMPATT diodes are presented. In addition the advantages of double drift structures over single drift structures are re-examined in the light of the suggestion that silicon and gallium arsenide IMPATT diodes are thermally and impedance limited rather than current density limited at high frequencies. The problem of tunnelling is also examined and is shown to be unimportant at all frequencies up to 120 GHz.     

Numerical analysis of a double avalanche region IMPATT diode on the basis of nonlinear model

The analysis of the n⁺pvnp⁺ avalanche diode structure has been realized on the basis of the nonlinear model. This type of the diode that was named as double avalanche region (DAR) IMPATT diode includes two avalanche regions inside the diode. The phase delay which was produced by means of the two avalanche regions and the drift region v is sufficient to obtain the negative resistance for the wide frequency band. The numerical model that is used for the analysis of the various diode structures includes all principal features of the physical phenomena inside the semiconductor structure. The admittance characteristics of the DAR diode were analyzed in very wide frequency band. The obtained results contradict to the before performed analysis on basis of the approximate models and show that only diode with a sufficiently short drift region can produce active power in some frequency bands.     

“Ideal” static breakdown in high-voltage (1 kV) 4<Emphasis Type="Italic">H</Emphasis>-SiC<Emphasis Type="Italic">p-n</Emphasis> junction diodes with guard ring termination

Nearly “ideal” static high-voltage breakdown (1060 V) in 4H-SiC p⁺-n-n⁺ diodes with guard ring termination is observed. At the doping level of 1.9 × 10¹⁶ cm^?3 in the n-type base, the diode breakdown field is 2.7 × 10⁶ V/cm. At the reverse bias as high as 1000 V, the leakage-current density does not exceed 5 × 10^?5 A/cm². The diodes withstand without degradation an avalanche-current density of 1 A/cm², which corresponds to the dissipated power of 1 kW/cm².     

Epitaxial layer induced series resistance and microwave properties of NNP Si X band impatt diodes

Following Gummel-Blue approach [1] [H.K. Gummel, J. L. Blue, IEEE Trans. Electron. Devices 14(1967) pp. 569-572.], the effect of undepleted epitaxial layers on the series resistance (R_s) as well as on its microwave properties of single drift region (n⁺np⁺) Si IMPATT diodes [2] [M. Mitra, M. Das, S. Kar, S.K. Roy, IEEE Trans. Electron. Devices 40(1993) pp. 1890-1893.] with flat doping profile with capacity 0.2PF at X band under experimental bias current of 25 mA and temperature 373 K have been studied. The computation for series resistance fits well with the device data for flat doping profile [2] [M. Mitra, M. Das, S. Kar, S.K. Roy, IEEE Trans. Electron. Devices 40(1993) pp. 1890-1893.]. The same study has also been simulated on its low-high-low (lhl) doping profile counterpart. The value of R_s increases approximately linearly with the increase of undepleted epi-layer thickness determined by the doping density for both flat and lhl structure. The value of R_s decreases remarkably as the doping profile changes from flat to lhl type.     

Computer study on GaAs Schottky barrier IMPATT diodes

Oscillation characteristics of GaAs Schottky barrier IMPATT diodes are studied by computer simulation. For a Schottky barrier-n-n⁺ structure, the Read condition and the just-punch-through condition are found to be optimum with respect to the efficiency and power at 30 GHz. In order to improve the efficiency, a superabrupt doping profile is proposed and a high efficiency of 32 per cent is predicted. Calculation of the frequency dependence of the efficiency shows that GaAs IMPATT diodes still have the potentiality of high efficiency oscillator at 100 GHz and they are a promising microwave source in mm-wave region.     

Computer-aided analysis of double drift region impatt diode

The results calculated by computer for the double drift region IMPATT diode oscillator on the 8 mm waveband are reported in this paper. A comparison between single and double drift devices concerning the power output and efficiency is given. The effect of doping profile, current density and RF voltage on the performances of these devices have also been investigated. The theoretical data of these double drift IMPATT oscillator and amplifier are provided.     

Heat flow resistance measurements of silicon p+-v-n+ diodes under forward and reverse biased conditions

A detailed study of the heat flow resistance measurements in a p⁺-v-n⁺ diode is studied in both forward and reverse biased conditions. Measurements are made by continuously switching the diode from the power dissipation state into the temperature measuring state. Safe operating power limits are identified for the diodes depending upon their mode of operation either as a microwave switch or as an IMPATT oscillator.     

双漂移(P+PNN+)雪崩二极管的计算机辅助分析

本文报道了8mm硅双漂移雪崩二极管的计算机计算结果,并把双漂移器件与单漂移(P⁺NN⁺型)器件进行了比较,从而证实双漂移器件在输出功率和效率等方面都具有优越性,同时还研究了掺杂分布、温度、直流偏置和高频调制电压对器件特性的影响。本文为设计毫米波段双漂移雪崩二极管振荡器和放大器提供了理论数据。     

IMPATT diode quasi-static large-signal model

A quasi-static large-signal model of an IMPATT diode with general doping profile is derived. The numerical solution of this model has been implemented in a Fortran IV program which executes economically. This model has been used to analyze large-and small-signal admittances of GaAs double-drift and quasi-Read IMPATT diodes. The small-signal results are in good agreement with calculations done using a linearized small-signal model. The large-signal calculations exhibit power and efficiency saturation when reasonable values of parasitic resistance are included and are in good agreement with experimental GaAs diode performance. The generalized quasi-static formulation simplifies analysis of IMPATT structures with arbitrary doping profiles, specifically those with distributed avalanche zones, by providing the correspondence between these devices and the Read diode model.     

Large-Signal Equivalent Circuits of Avalanche Transit-Time Devices

A large-signal analysis for IMPATT diodes is derived, which allows carrier multiplication by impact ionization to occur at every point in the diode. Therefore, the operating characteristics of IMPATT diodes with a wide range of realistic doping profiles can be investigated. For a given operating frequency, RF voltage, dc bias current, and doping profile, the admittance, power output, efficiency, bias voltage of a diode can be obtained. An equivalent circuit the diode package, microwave circuit mount and diode, is obtained experimentally. Using this circuit, the admittance of the diode is measured by a reflection-type circuit and an oscillator circuit as a function of the RF voltage, dc bias current, and frequency.     

Highly conducting and transparent Ga2O3 doped ZnO thin films prepared by thermal evaporation method

Amorphous zinc oxide thin films are obtained by thermally evaporating pure zinc oxide powder. Films obtained have an excellent conductivity of 90 ??^?1 cm^?1 with transparency of up to 90% in the visible region. On doping with gallium oxide a great improvement in the conductivity of up to 8.7 × 10³ ??^?1 cm^?1 is observed and the optical band gap of the films is decreased from 3.25 to 3.2 eV, retaining the transparency. Measurements of activation energy show that the doped ZnO film has one donor level at 68 meV and other at 26 meV bellow the conduction band.     

Influence of doping with third group oxides on properties of zinc oxide thin films

The study of modifications in structural, optical and electrical properties of vacuum evaporated zinc oxide thin films on doping with III group oxides namely aluminum oxide, gallium oxide and indium oxide are reported. It was observed that all the films have transmittance ranging from 85 to 95%. The variation in optical properties with dopants is discussed. On doping the film with III group oxides, the conductivity of the films showed an excellent improvement of the order of 10³ Ω^?1 cm^?1. The measurements of activation energy showed that all three oxide doped films have 2 donor levels below the conduction band.     

Small-signal analysis of punch-through injection microwave devices

A theoretical small-signal analysis of punch-through injection microwave devices is given. A numerical study of a silicon p⁺?n?p⁺ structure is performed, which shows good agreement with experimental measurements by Snapp and Weissglas for a diode with a doping density of 1·2 × 10¹⁵/cm³. Negative resistance is also calculated for diodes with doping densities of 0·6 × 10¹⁵/cm³ and 5 × 10¹⁵/cm³. A partially analytical mode, including the lowfield region, is developed and compared with the numerical calculation. Ohmic losses for devices with low impurity concentrations and diffusion for devices with high impurity concentrations are shown to be significant factors.The noise spectrum is calculated numerically from the assumption of two noise sources, injection noise and diffusion noise. The noise measure is determined and shown to be in good agreement with experiments by Björkman and Snapp.     

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.     

Dynamic minority-carrier storage in TRAPATT diodes

The occurrence of a dynamic storage of minority carriers in the highly-doped boundary regions of a TRAPATT diode and the subsequent release of these carriers into the diode's depletion region is verified for the first time in detailed computer simulations of the diode's internal dynamics. The simulations were carried out by numerical solution of the carrier transport equations in a p⁺?n?n⁺ silicon diode having a deep-diffused doping profile typical of experimental devices. The results show that it is this storage process, and not thermal generation, that controls the carrier avalanche even in very gradually graded structures. The dynamics of this phenomenon are described in detail and the implications of the results on TRAPATT oscillator performance are discussed.