Diffusion capacitance

About: Diffusion capacitance is a research topic. Over the lifetime, 2427 publications have been published within this topic receiving 33948 citations.

Junction Diameter Dependence of Oscillation Frequency of GaN IMPATT Diode Up to 21 GHz

Abstract: An experimental study on the effects of junction capacitance and current density on the oscillation characteristics of GaN single-drift-region (SDR) impact ionization avalanche transit-time (IMPATT) diodes were carried out using GaN p+-n abrupt junction diodes of various diameters, 200, 150, and 100 μm, with a depletion layer width of 2 μm. The fabricated diodes showed a clear avalanche breakdown at 315 V and a pulsed microwave oscillation with a peak output power exceeding 30 dBm. The oscillation frequency depended on junction diameter and current density. It was widely modulated from 8.56 to 21.1 GHz with decreasing junction diameter and increasing current density. The highest oscillation frequency was obtained with a current density of 13.8 kA/cm2 and a junction diameter of 100 μm. A numerical calculation based on Read-type small-signal theory was carried out and found to well explain the experimental results.

Output Nonlinearity Caused by Junction Capacitance of Switches in the Auxiliary Resonant Commutated Pole Soft-Switching Inverter

Abstract: Output current nonlinearity error is the key problem which leads to nanometer positioning error in ultra-precision positioning applications. The auxiliary resonant commutated pole inverter (ARCPI) as a zero-voltage switching inverter has the advantage of low dead-time effect. However, the junction capacitances of switches are also one of the error sources in the converter, which hasn’t analyzed before. Therefore, the output nonlinearity caused by junction capacitance of switches in the ARCPI is researched. In this paper, the converter model considering the junction capacitances is built. The commutation considering the junction capacitances is analyzed. The output voltage error caused by the junction capacitances is calculated. A prototype was developed to verify the effectiveness of proposed methods.

Enhanced Diffusion of Substrate Impurities into Epitaxial Layers in Si by Proton Irradiation

Abstract: Enhanced diffusion of n+ substrate impurities Sb and P into epitaxial layers in Si by proton irradiation is observed and analyzed using a simple Gaussian impurity diffusion coefficient in terms of steady state excess vacancy distribution. The maximum diffusion coefficients obtained when 30µA/cm2 proton beams at 300 to 450 kV are used at 900°C are 4000 to 7000 times as large as the thermal diffusion coefficients for Sb and P in Si. The standard deviation of 1µm or a little smaller for the Gaussian diffusion coefficient is reasonable for 300 to 450 kV proton irradiation. The vacancy lifetime and the diffusion length are estimated to be of the order of magnitude of 10-5 sec and 0.1 µm, respectively. Enhanced diffusion techniques are applied to the formation of pillar-like collectors for an npn microwave transistor. The power gain is improved by 1 db at 4 GHz by the reduction of parasitic base-collector junction capacitance.

Coarse tuning and fine tuning combined high-frequency LC voltage-controlled oscillator and tuning method

Abstract: The invention discloses a coarse tuning and fine tuning combined high-frequency LC voltage-controlled oscillator and a tuning method The coarse tuning and fine tuning combined high-frequency LC voltage-controlled oscillator consists of an LC resonant network circuit and a common emitter amplifier circuit, wherein the LC resonant network of the circuit is coarsely tuned through the voltage-controlled end by adopting a capacitive impedance form that a variable capacitance diode acts as the reactance in the LC resonant network, is finely tuned through the voltage-controlled end by adopting an inductive reactance branch form that another variable capacitance diode acts as the reactance in the LC resonant network, and has two voltage-controlled tuning ends which are the coarse tuning end and the fine tuning end By adjusting the magnitude of the reverse bias voltage of the variable capacitance diodes and changing the junction capacitance of the variable capacitance diodes through the combined coarse tuning and fine tuning, the resonant frequency of the resonant network can be changed, and the frequency of the output signals can be finally changed The coarse tuning and fine tuning combined high-frequency LC voltage-controlled oscillator and the tuning method disclosed by the invention are less in components and parts, simple in circuit and larger in application, achieve an economical and efficient method for generating high-frequency oscillators, and can be widely applied to mobile phones, satellite communication terminals, base stations, radars, digital wireless communication systems and other electronic systems