Doppler Frequency Multiplication by a Semiconductor Depletion Layer

Nature ◽  
1962 ◽  
Vol 196 (4857) ◽  
pp. 884-885
Author(s):  
O. P. GANDHI
Keyword(s):  
Doppler Frequency ◽  
Depletion Layer ◽  
Frequency Multiplication

Electron beam induced current study of thin silicon layers on insulator substrate

1990 ◽  
Vol 48 (4) ◽  
pp. 618-619
Author(s):  
A. Buczkowski ◽  
Z. J. Radzimski ◽  
J. C. Russ ◽  
G. A. Rozgonyi
Keyword(s):  
Electron Beam ◽  
Energy Loss ◽  
Beam Energy ◽  
Collection Efficiency ◽  
Silicon Layer ◽  
Depletion Layer ◽  
Incident Electron Energy ◽  
Induced Current ◽  
Electron Hole ◽  
Electron Beam Induced Current

If a thickness of a semiconductor is smaller than the penetration depth of the electron beam, e.g. in silicon on insulator (SOI) structures, only a small portion of incident electrons energy , which is lost in a superficial silicon layer separated by the oxide from the substrate, contributes to the electron beam induced current (EBIC). Because the energy loss distribution of primary beam is not uniform and varies with beam energy, it is not straightforward to predict the optimum conditions for using this technique. Moreover, the energy losses in an ohmic or Schottky contact complicate this prediction. None of the existing theories, which are based on an assumption of a point-like region of electron beam generation, can be used satisfactorily on SOI structures. We have used a Monte Carlo technique which provide a simulation of the electron beam interactions with thin multilayer structures. The EBIC current was calculated using a simple one dimensional geometry, i.e. depletion layer separating electron- hole pairs spreads out to infinity in x- and y-direction. A point-type generation function with location being an actual location of an incident electron energy loss event has been assumed. A collection efficiency of electron-hole pairs was assumed to be 100% for carriers generated within the depletion layer, and inversely proportional to the exponential function of depth with the effective diffusion length as a parameter outside this layer. A series of simulations were performed for various thicknesses of superficial silicon layer. The geometries used for simulations were chosen to match the "real" samples used in the experimental part of this work. The theoretical data presented in Fig. 1 show how significandy the gain decreases with a decrease in superficial layer thickness in comparison with bulk material. Moreover, there is an optimum beam energy at which the gain reaches its maximum value for particular silicon thickness.

Carrier Redistribution Analysis of Gate-Biased SiC Power-MOSFET Using Super-Higher-Order Scanning Nonlinear Dielectric Microscopy

2015 ◽  
Author(s):  
Norimichi Chinone ◽  
Yasuo Cho
Keyword(s):  
Cross Section ◽  
Measurement System ◽  
Higher Order ◽  
Depletion Layer ◽  
Gate Bias ◽  
Power Mosfet ◽  
Nonlinear Dielectric ◽  
Voltage Dependent ◽  
Carrier Redistribution ◽  
Source Voltage

Abstract Gate-bias dependent depletion layer distribution and carrier distributions in cross-section of SiC power MOSFET were measured by newly developed measurement system based on super-higher-order scanning nonlinear dielectric microscope. The results visualized gate-source voltage dependent redistribution of depletion layer and carrier.

Nanoscale Capacitance and Capacitance-Voltage Curves for Advanced Characterization of Electrical Properties of Si and GaN Structures Using Scanning Microwave Impedance Microscopy

2016 ◽  
Author(s):  
Stuart Friedman ◽  
Oskar Amster ◽  
Yongliang Yang ◽  
Fred Stanke
Keyword(s):  
Process Development ◽  
Advanced Characterization ◽  
Electrical Measurement ◽  
Depletion Layer ◽  
Doped Semiconductors ◽  
Force Microscopy ◽  
Nano Scale ◽  
Capacitance Voltage ◽  
Systematic Response ◽  
Lock In

Abstract The use of Atomic Force Microscopy (AFM) electrical measurement modes is a critical tool for the study of semiconductor devices and process development. A relatively new electrical mode, scanning microwave impedance microscopy (sMIM), measures a material’s change in permittivity and conductivity at the scale of an AFM probe tip [1]. sMIM provides the real and imaginary impedance (Re(Z) and Im(Z)) of the probe-sample interface. By measuring the reflected microwave signal as a sample of interest is imaged with an AFM, we can in parallel capture the variations in permittivity and conductivity and, for doped semiconductors, variations in the depletion-layer geometry. An existing technique for characterizing doped semiconductors, scanning capacitance microscopy, modulates the tip-sample bias and detects the tip-sample capacitance with a lock-in amplifier. A previous study compares sMIM to SCM and highlights the additional capabilities of sMIM [2], including examples of nano-scale capacitance-voltage curves. In this paper we focus on the detailed mechanisms and capabilities of the nano-scale C-V curves and the ability to extract semiconductor properties from them. This study includes analytical and finite element modeling of tip bias dependent depletion-layer geometry and impedance. These are compared to experimental results on reference samples for both doped Si and GaN doped staircases to validate the systematic response of the sMIM-C (capacitive) channel to the doping concentration.

A FrFT Based Algorithm for Doppler Frequency Rate Estimation from LFM Coherent Pulse Train

2010 ◽  
Vol 32 (11) ◽  
pp. 2718-2723 ◽  
Author(s):  
Hong Li ◽  
Yu-liang Qin ◽  
Yan-peng Li ◽  
Hong-qiang Wang ◽  
Xiang Li
Keyword(s):  
Pulse Train ◽  
Doppler Frequency ◽  
Rate Estimation ◽  
Frequency Rate ◽  
Coherent Pulse

scholarly journals RF Transceiver for the Multi-Mode Radar Applications

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1563
Author(s):  
Jae Kwon Ha ◽  
Chang Kyun Noh ◽  
Jin Seop Lee ◽  
Ho Jin Kang ◽  
Yu Min Kim ◽  
...  
Keyword(s):  
Long Range ◽  
Integrated Circuit ◽  
Flicker Noise ◽  
Noise Figure ◽  
Supply Voltage ◽  
Doppler Frequency ◽  
Cmos Process ◽  
Rf Transceiver ◽  
Dc Offset ◽  
Multi Mode

In this work, a multi-mode radar transceiver supporting pulse, FMCW and CW modes was designed as an integrated circuit. The radars mainly detect the targets move by using the Doppler frequency which is significantly affected by flicker noise of the receiver from several Hz to several kHz. Due to this flicker noise, the long-range detection performance of the radars is greatly reduced, and the accuracy of range to the target and velocity is also deteriorated. Therefore, we propose a transmitter that suppresses LO leakage in consideration of long-range detection, target distance, velocity, and noise figure. We also propose a receiver structure that suppresses DC offset due to image signal and LO leakage. The design was conducted with TSMC 65 nm CMOS process, and the designed and fabricated circuit consumes a current of 265 mA at 1.2 V supply voltage. The proposed transmitter confirms the LO leakage suppression of 37 dB at 24 GHz. The proposed receiver improves the noise figure by about 20 dB at 100 Hz by applying a double conversion architecture and an image rejection, and it illustrates a DC rejection of 30 dB. Afterwards, the operation of the pulse, FMCW, and CW modes of the designed radar in integrated circuit was confirmed through experiment using a test PCB.

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