Optoelectronic%20Simulation%20of%20PhotoDetectors

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Optoelectronic Simulation of PhotoDetectors

• Tarun Parmar
• Microrelectronic Engineering
• R.I.T.

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Outline

• Introduction
• Comparison of Photodetectors
• Photon detection
• Device Simulation
• Optoelectronic Device Simulator
• Results

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Introduction

• The poster presents simulation of recombination
  rate and quantum efficiency of an photodetector
  (photodiode) being fabricated at RIDL.
• Simulated total integrated recombination rate
  significantly contributes to the reverse diode
  leakage current.
• Quantum efficiency is defined as the ratio of the
  number of carriers detected at a given
  photodetector electrode divided by the number of
  incident photons on the detector.

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Comparison of Photodetectors

• Generic Operating Parameters of Si, Ge, and GaAs
  pin Photodiodes

Parameter Symbol Unit Si Ge InGaAs
Wavelength Range ? nm 400-1100 800-1650 1100-1700
Responsivity R A/W 0.4-0.6 0.4-0.5 0.75-0.95
Dark current ID nA 1-10 50-500 0.5-0.2
Rise time tr ns 0.5-1 0.1-0.5 0.05-0.5
Bandwidth B GHz 0.3-0.7 0.5-3 1-2
Bias Voltage VB V 5 5-10 5
Source Optical Communications Essentials, Gerd
Keiser, pp 113.
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Photon Detection

• pin photodiode operated in reverse bias
• p high acceptor concentration
• intrinsic (lightly) doped material
• n high donor concentration
• I-V characteristics of pin photodiode
• (1) with no light
• (2) with light

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Device Simulation
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Optoelectronic Device Simulator

• Luminous is an advanced simulator used to model
  absorption and photogeneration in semiconductor
  devices

Silvaco Athena simulation tool
Process simulation uses Athena Electrical
simulation uses Atlas, Luminous Graphs are
generated using Tonyplot
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Tonyplot Results (1)
Quantum Efficiency
Recombination Rate 0.258 e-/sec/pixel
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Tonyplot Results (2)
Electric field in 2D
Electric field in 3D