P-N junction lasers

A review of p-n junction injection lasers is presented. The literature published up to November, 1963, is fairly completely covered as well as a number of preprints. Also, included in the end is a section covering "recent work."     

The tunneling P-N junction

The tunneling probability in an Esaki diode is very much dependent on the electric field strength which is itself dependent on the local fluctuations of ion concentration. The fluctuation of depletion layer thickness due to randomness of ion position is calculated. It is shown that most of the tunneling current is carried by only a small fraction of the total area.     

Avalanche breakdown characteristics of a diffused P-N junction

A one-dimensional analysis is presented on the avalanche breakdown characteristics of a diffused p-n junction diode. By numerically integrating the carrier ionization rate in a junction space-charge layer, avalanche breakdown voltage is calculated for diffused diodes of silicon and germanium; this voltage is graphically illustrated throughout a range of parameters applicable to most practical situations. In addition, for calculating the maximum cutoff frequency of varactor diodes, junction capacity is similarly illustrated assuming the device is biased to avalanche breakdown. From these illustrations, and from an accompanying nomograph which relates the physical constants of a junction to its impurity atom gradient, the above parameters can be readily established without additional calculations. Further, examples are also presented to demonstrate the reduction of breakdown voltage resulting from a rapid increase of conductivity within the space-charge layer of a diffused p-n junction; this situation approximates many epitaxial and double diffused structures.     

Reverse transient characteristics of a P-N junction diode due to minority carrier storage

Analysis of the transient switching characteristics of a p-n junction diode is considered a boundary value problem; solution of this problem yields mathematical equations applicable to the design of high-speed computer components. This analytical technique is used to establish the transient current of a semiconductor diode when an external biasing potential is rapidly switched from the forward to the reverse direction. Using a one-dimensional model of finite geometry, minority-carrier storage is assumed within a region of arbitrary lifetime, bounded on one side by the junction and on the other side by an ohmic contact of arbitrary recombination velocity. Further, this region of carrier storage is assumed to contain a drift field of constant magnitude as would result from an exponential type of conductivity grading. Mathematical equations are presented which characterize this transient situation from its initiation until the junction current has decayed to some arbitrary magnitude. Applications of this analysis are illustrated in graphical form throughout a range of parameters characterizing practical semiconductor devices.     

Analysis and characterization of P-N junction diode switching

A new charge control model of a p-n junction diode is introduced in which the reverse current iRas well as the forward current IFare related to the chargeQstored in the base region by time constants τRand τF, respectively. The reverse switching transient is analyzed for normal switching operation where a constant current phase (storage phase) and a decaying current phase exist, and for overdriven switching operation where no constant current phase exists. New switching time equations are derived. The equations are expressed in terms of measurable device parameters τF, τR, and Cjexternal circuit variables IFand IRand an external circuit parameter R. The proposed model is applicable to p-n junction diodes of any type. Experimental results using various types of diodes are also reported. It is shown that the experimental results are in very good agreement with the theory.     

Problems related to the avalanche and secondary breakdown of silicon P-N junction

The paper provides an analysis of some still unsolved problems related to avalanche and secondary breakdown. An evaluation is given of four models of energy accumulation, necessary for impact ionization: Wolf's diffusion model, Shockley's model of ‘lucky’ electrons, Ridely's model of ‘lucky-drift’ and Gribnikov's model of ‘light’ electrons. It is shown that impact ionization is mainly realized in conformity with the model of ‘light’ charge carriers.It is indicated that the bright avalanche breakdown channels, called microplasmas, are encircled by a weakly shining ring-shaped cloud. Apparently this cloud is caused by the ‘light’ charge carriers. As the p-n junction is heated under the influence of a high avalanche breakdown current and reaches a certain temperature, the luminous clouds expand and by force of the magnetic pinch created by the current itself tend towards the centre, where they meet and assume the form of a ring. Then the weakly shining cloud (pre-mesoplasma) contracts rapidly and bright circular mesoplasma lights up (secondary breakdown appears) which moves in the direction of higher temperature and higher voltage until it localizes at a large defect or contact. A model is proposed according to which pre-mesoplasma and mesoplasma is a flow of ‘light’ charge carriers. This model allows us to explain many peculiarities of pre-mesoplasma and mesoplasma.     

Fabrication of self-aligned graded junction termination extensions with applications to 4H-SiC P-N diodes

The properties of SiC make this wide band-gap semiconductor a promising material for high power devices. This potential is demonstrated in various devices, such as p-n diodes, Schottky diodes, bipolar junction transistors, thyristors, etc., all of which require adequate and affordable termination techniques to reduce leakage current and increase breakdown voltage in order to maximize power-handling capabilities. In this paper, we describe a technique for fabricating a graded junction termination extension (GJTE) that is effective and self-aligned, a feature that simplifies the implantation process during fabrication and, therefore, has the potential to reduce production costs. Implanted anode p-n diodes fabricated using this technique on 10-μm thick n⁻ epitaxial layer had a maximum breakdown voltage of 1830 V. This was comparable to the ideal parallel-plane breakdown of 1900 V predicted by numerical simulation.     

线性色散缓变光纤中孤子传输特性

运用行波解法求解了色散缓变光纤中的非线性薛定谔方程 ,可以得到近似形式的解析解 ,并得到了孤子振幅、中心位置、相位的演化方程。在此基础上研究了线性色散对孤子振幅、中心位置、相位等传输特性的影响。     

Design theory and experiments for abrupt hemispherical P-N junction diodes

The gold-bonded germanium diode offers a practical example of a hemispherical p-n junction. In this discussion, a theory is given for the parameters of interest in design for such a junction; i.e., the breakdown voltage, forward current, and transient effects. It is shown that voltage breakdown differs from that for a planar junction due to the concentration of the field by the geometry, this effect leading to lower breakdown voltages. The forward current and reverse transient dependence on the radius of the junction, bulk properties, and the thickness of the semiconductor, are shown. The nature of the back contact to the semiconductor is also discussed. Since this is a design theory, rigor is sacrificed in some cases for simplicity. Despite this, comparison of the theoretical predictions with experimental results usually shows good agreement. The possibility of applying the results to other hemispherical geometries, such as point contact diodes, is considered briefly.     

An electrochemical P-N junction etch-stop for the formation of silicon microstructures

An electrochemical technique allowing the protection of selected areas of silicon in ethylene diamine-based etchants is reported, and its application to the formation of silicon microstructures is described. Dissolution rates for passivated samples are less than 5 Å/minute, a factor of over 3000 times less than for unpassivated silicon.     

Forward transient behavior of P-N junction diodes at high injection levels

By use of the finite-difference method of numerical analysis, a detailed numerical solution is obtained for the complete one-dimensional continuity equation, to study the transient and steady-state behavior of p-n junction diodes at moderate-to-high injection levels. The solution of the continuity equation is obtained for minority carriers in the base of a diode under the influence of drift, diffusion, and recombination. From the calculated distribution of minority carriers in the base, minority-carrier and majority-carrier currents and their components are obtained. The electric field and its components in the base are determined, and the total voltage across the diode and its components are calculated. All results are obtained for transient and steady-state conditions. The effect of variations of certain physical parameters on the diode behavior is investigated. All calculations were performed on the IBM 709 digital computer.     

P-N junction observations on Pb-salt diode lasers using an ebic-mode SEM

A scanning electron microscope (SEM) operating in the elec-tron- beam induced current (EBIC) mode has been used to determine the depths and uniformities of p- n junctions in a variety of Pb- salt diode lasers. Pb- salt materials with 20K band gap values ranging from 44 meV to 450 meV have been investigated. This includes the ternary alloy systems Pb_1−xCd_xS(with 0 ≤ x ≤ 0.048), PbS_1-xSe_x (with 0 ≤ x ≤ l), Pb_1−xSn_xSe (with O ≤ x ≤ O.10),and Pb_1-xSn_xTe (with x = 0.25). With typical carrier concentrations in the 10¹⁸ – 10¹⁹ cm^{− 3} range, the junction depths were found to be independent of temperature between 77K and 300K. Small band gap devices exhibited EBIC signals strongly dependent on T, while devices with band gap values above 130 meV at 77K exhibited relatively little such temperature dependence to 300K. This non- destructive technique is capable of providing junction depth and uniformity information of all the Pb-salt materials, and is useful for estimating minority car-rier diffusion lengths at various temperatures. The method is also useful for investigating some of the more complex confinement heterostructures in these materials.     

双结型硅色敏器件的测试与分析

测试发现双结型硅色敏器件的两个结的输出电流与测试方法有关，对此进行了分析，并给出了正确的测试方法，对色敏器件的制作工艺提出了若干改进意见。     

Effect of surface recombination and channel on P-N junction and transistor characteristics

The current flowing in a semiconductor junction may be divided into four components according to the location of the recombination and generation of electrons and holes. These are: 1) the bulk recombination-generation or the diffusion current, 2) the bulk recombination-generation current in the transition region, 3) the surface recombination-generation current in the transition region, and 4) the surface channel current. The current-voltage relationship for these four current components may be approximated byI = I_{s} exp (qV/mkT), ifV > 4kT/q. Analysis shows that the reciprocal slopemfor the current components 1) to 3) lies between 1 and 2, while for the surface channel current component 4)mis greater than 2 for silicon junctions and may be more than 4 for large channels. The theoretical expressions for these four current components are tested with extensive experimental data taken on silicon junctions and found to account for all of the observed current-voltage characteristics. The importance of surface recombinations and surface channels on the current gain of silicon transistor is also demonstrated experimentally. The experimental data are in accord with the theoretical prediction based on the transistor current equations which include the carrier recombination in the emitter junction and the carrier generation in the collector junction.     

Planar, ion implanted, high voltage 6H-SiC P-N junction diodes

Planar, high voltage (800 V) P-N junction diodes have been fabricated for the first time on N-type 6H-SiC by room temperature boron implantation through a pad oxide deposited within windows etched in an LPCVD field oxide. All the diodes showed excellent rectification with leakage currents of less than 10 nA (~5×10^-5 A/cm² ) until avalanche breakdown. It was found that the breakdown voltage increases with junction depth. The reverse recovery time (t_rr) was measured to be 50 ns for the 800 V diode from which an effective minority carrier life time of 12.5 ns was extracted     

Transient response of a tunnel-diode trigger for linearly varying current pulses

The pertinent forward and reverse transient characteristics of a tunnel diode for a ramp input are analytically investigated. A comparison with the results of a step input shows that the slope of the trigger pulse greatly affects the initial development of the process. The results for a linear piecewise approximation are also presented to estimate the deviation from the actual results.     

Characterisation of linearly graded p-n junction

Electrostatic potential, carrier densities and space charge density distributions have been calculated using an iterative scheme for linearly graded p-n junction. It is found that the results obtained from this scheme are close to those given by rigorous numerical formulations, especially at applied forward bias. As an application of this scheme the charge-defined emitter space-charge-layer transit time has been calculated and results compared with those of numerical algorithms.     

Exchange switching of a magnetic junction by a current pulse

Results of numerical simulation of switching of a magnetic transition induced by a spin-polarized current pulse in the presence of an external magnetic field for a current density and a field strength that are lower than the corresponding threshold values are presented. The magnetic field regenerates the system and drives it to the threshold of an orientation phase transition, which simplifies exchange switching induced by a current pulse. This switching is characterized by the same locality as the exchange interaction, i.e., it is local at atomic lengths. It is demonstrated that there exists the possibility of switching with a controllable delay with respect to the current pulse.     

Optical response of a stripe-geometry junction laser to sinusoidal current modulation at 1.2 GHz

Measurements of the intensity modulation induced on the optical output of a proton-bombarded stripe-geometry junction laser by sinusoidal modulation of the laser current at 1200 MHz are reported. Emission occurs in short pulses at any bias current if the current modulation is sufficiently Strong, but only at bias currents which place the laser's internal resonance in the vicinity of one half or one times the modulating frequency if the current modulation is weak. The apparent threshold for lasing is shown to decrease when the RF modulation depth reaches 100 percent, but linearity of the current dependence of the average output power is not maintained at high optical power levels.