Designing a Waveguide Photodetector in Rsoft

The following images depict the first stages of a waveguide photodetector design in Rsoft., The input waveguide is 2 microns, followed by a tapered section to a 10 micron wide photodetector region. Three tapering typologies are used. Following these initial simulations come optimization of the photodetector region and electrical simulations.

First, the layer view. This section is at the input waveguide.

The InGaAs layers above the waveguide serve to absorb the optical power in the photodetector region:

Three different input tapers are used:

Exponential Taper:

Absorption in the photodetector region is in the range of 95%.

Quadratic Taper:

Here is the optical power remaining in the waveguide region:

Linear Taper:

High Speed UTC Photodetector Simulation with Frequency Response in TCAD

The following is a TCAD simulation of a high speed UTC photodetector. An I-V curve is simulated for the photodetector, forward and reverse. A light beam is simulated to enter the photodetector. The photo-current response to a light impulse is simulated, followed by a frequency response in TCAD.



I-V Curve


Beam Simulation Entering Photodetector:



Light Impulse:


Frequency Response in ATLAS:


The full project (pdf) is here: ece530_final_mbenker


High Speed Waveguide UTC Photodetector I-V Curve (ATLAS Simulation)

The following project uses Silvaco TCAD semiconductor software to build and plot the I-V curve of a waveguide UTC photodetector. The design specifications including material layers are outlined below.

Simulation results

The structure is shown below:



Forward Bias Curve:


Negative Bias Curve:


Current Density Plot:


Acceptor and Donor Concentration Plot:


Bandgap, Conduction Band and Valence Band Plots:



Construct an Atlas model for a waveguide UTC photodetector. The P contact is on top of layer R5, and N contact is on layer 16. The PIN diode’s ridge width is 3 microns. Please find: The IV curve of the photodetector (both reverse biased and forward bias).

The material layers and ATLAS code is shown in the following PDF: ece530proj1_mbenker