This paper presents theoretical calculations of the large-signal admittance and efficiency achievable in a silicon p-n-v-ns Read IMPATT diode. A simplified theory is employed to obtain a starting design. This design is then modified to achieve higher efficiency operation as specific device limitations are reached in large-signal (computer) operation. Self-consistent numerical solutions are obtained for equations describing carrier transport, carrier generation, and space-charge balance. The solutions describe the evolution in time of the diode and its associated resonant circuit. Detailed solutions are presented of the hole and electron concentrations, electric field, and terminal current and voltage at various points in time during a cycle of oscillation. Large-signal values of the diode's negative conductance, susceptance, average voltage, and power-generating efficiency are presented as a function of oscillation amplitude for a fixed average current density. For the structure studied, the largest microwave power-generating efficiency (18 percent at 9.6 GHz) has been obtained at a current density of 200 A/cm2, but efficiencies near 10 percent were obtained over a range of current density from 100 to 1000 A/cm2.

Large-signal analysis of a silicon Read diode oscillator

Equations are presented which fit the experimental dependence of carrier mobilities on doping density and field strength in silicon. The curve-fitting procedures are described.

Carrier mobilities in silicon empirically related to doping and field

This paper reviews the present knowledge of charge transport properties in silicon, with special emphasis on their application in the design of solid-state devices. Therefore, most attention is devoted to experimental findings in the temperature range around 300 K and to high-field properties. Phenomenological expressions are given, when possible, for the most important transport quantities as functions of temperature, field or impurity concentration. The discussion is limited to bulk properties, with only a few comments on surface transport.

A review of some charge transport properties of silicon

This article reviews the progress made in the studies of copper in silicon over the last several years and puts forward a comprehensive model of the behavior of copper in silicon. Technical aspects of this model are discussed in detail. It is shown that many important aspects of the behavior of copper in silicon are not shared with the other 3d transition metals. The positive charge state of interstitial copper makes its defect reactions Fermi-level-dependent, and results in a noticeable difference in the out-diffusion and precipitation behavior of copper in n-Si and p-Si. The extremely high diffusivity of copper in silicon, which is a consequence of the small ionic radius of copper and its relatively weak interaction with the silicon lattice, makes it highly mobile at room temperature and impacts the stability of copper complexes. Large lattice strains and electrostatic effects in p-Si make the formation of copper-silicide precipitates in the hulk energetically unfavorable, unless the chemical driving force for precipitation is high enough to overcome the nucleation and precipitation harrier. Literature data on the effect of copper on minority carrier lifetime and device yield are analyzed using our improved understanding of the physics of copper in silicon. Finally, the impact of the physics of copper in silicon on the development and characterization of copper diffusion barriers is discussed.

Physics of Copper in Silicon

A series of gettering experiments have been carried out for a better understanding of gettering mechanism(s) in silicon. We find that oxidation and oxynitridation, which are known to inject silicon interstitials, do not getter metallic impurities such as Au, Cu, Fe, and Ni while phosphorus (P) diffusion does produce effective gettering of these metals. We also find from P diffusion, Ar ion implantation, and Ni film gettering performed as a function of temperature, there exists an optimum gettering temperature. From a comprehensive discussion of the existing models, we conclude that neither the enhanced metal solubility nor the silicon interstitial model explains our experimental results. Furthermore, it is shown that generation of dislocations is not a prerequisite for effective gettering. A model, based on the segregation of impurities at high temperatures and on the release/diffusion of metallic impurities at lower temperatures, is proposed to explain all of our results. A general form of the segregatio...

T.E. Seidel

Papers

Enhanced solubility and ion pairing of Cu and Au in heavily doped silicon at high temperatures

Dependence of hole velocity upon electric field and hole density for p-type silicon