2D Optoelectronics Device Simulator

Luminous is an advanced device simulator specially designed to model light absorption and photogeneration in non-planar semiconductor devices. Exact solutions for general optical sources are obtained using geometric ray tracing. This feature enables Luminous to account for arbitrary topologies, internal and external reflections and refractions, polarization dependencies and dispersion. Luminous also allows optical transfer matrix method analysis for coherence effects in layered devices. The beam propagation method may be used to simulate coherence effects and diffraction. Luminous is fully integrated within Atlas with a seamless link to S-Pisces and Blaze device simulators, and other Atlas device technology modules.

Luminous can simulate mono-chromatic or multi-spectral optical sources, and provides special parameter extraction capabilities unique to optoelectronics. DC, AC, transient, and spectral optical responses of general device structures can be simulated in the presence of arbitrary optical sources. Luminous is applicable to a wide array of device technologies including CCDs, solar cells, photodiodes, photoconductors, avalanche photodiodes, MSM photodetectors, phototransistors, and optoelectronic imaging arrays and many more.

Charged Coupled Devices and Imaging Devices (CCDs)

Luminous performs detailed analysis of imaging arrays and CCD devices.

A device structure plot of a micro-lens CCD created with Athena. The geometric ray trace data generated by Luminous is overlaid on the structure. Geometric ray tracing capabilities enable the analysis of complex non-planar structures for optimizing collection efficiency and reducing cross-talk. The photogeneration rate is calculated based on the local optical intensity provided by the ray tracing.

 

Time sequence of electron concentration contours during charge transfer in a buried channel CCD. This type of analysis is used to extract charge well capacity and charge transfer efficiency.
A common application of Luminous is the evaluation of potential in a CCD channel during a transfer cycle. The evaluation of vertical cross-sections at several x-axis locations is used to illustrate the peak potential across the device channel.

 

High Speed and Communication Photodectors

Luminous analyzes photodetectors used in high speed and low noise applications such as communications hardware. It provides a cost effective solution for optimizing device structures.

Impact ionization rate contours at operating bias for a Reach Through Avalanche Photodiode (RAPD). An important feature of this device is the n-type guard ring that is used to prevent premature breakdown at the edges of the front surface n-region.

The peak impact ionization region is in the intended multiplication region. Luminous enables easy evaluations of different device structures and guard ring geometries.

Important device characteristics such as quantum efficiency, spectral response, and frequency response are easily extracted using Luminous. Shown is the response to a high frequency variable light source. Luminous also permits simulation of transient response. Here the lag between a rapid turn-off of the light and the resultant photodetected current.
Luminous allows the specification and simulation of multi-layer anti-reflective coatings. Shown is a comparison of the spectral response of a device with and without anti-reflective coatings as compared to the ideal response. Luminous allows very general specification of the optical source. In this example we show a Gaussian source intensity, with non-normal incidence and periodic boundaries.

 

Solar Cells

Solar cell characteristics such as collection efficiency, spectral response, open circuit voltage, and short circuit current can be extracted with Luminous.

By varying the incident wavelengths, a spectral response can be modeled. The green curve is the current from the light source, and the blue curve is the actual terminal current. The ray trace features in Luminous enable the analysis of advanced designs. Shown above is the simulation of photogeneration rates from an angled light beam.

 

Beam Propagation Method

Luminous includes physical models that take into account the wave nature of light. Diffraction of light as well as coherent effects can be analyzed using beam propagation method.

Beam propagation method in Luminous takes into account diffraction of light. Spreading of a narrow Gaussian beam due to diffraction affects the distribution of photogenerated carriers in Silicon.
Beam propagation method in Luminous can be used for analysis of light propagation in complex structures. Light reflection and refraction on a Silicon oxide / Silicon boundary is shown in this figure. Interference of incident and reflected light is taken into account.

 

High Intensity Optical Beams for Rapid Thermal Annealling Applications

Optical beams are used in semiconductor processing for rapid thermal anneals of whole wafers using infraread lamps or for localized re-crystalization using a high intensity laser beam swept across the wafer in a raster fashion.

Both of these applications can be simulated directly using Luminous in conjunction with Giga to model the temperature rise from the optically stimulated electron-hole pair recombination processes.

The examples on this page depict the transient localized temperature evolution of a high intensity laser beam being swept across the surface of a silicon substrate in the Z direction.

The first two figures show the evolution of temperature rise as the the 10um wide, 1MW/cm2 green laser beam is illuminated for 5 and 10 microseconds respectively. After 10 microseconds the beam is switched off to simulated it being swept in the Z direction, and the final two graphics show how the heat dissipates with time in 5 microsecond intervals. Temperature rise at the surface of the wafer at the center of the laser beam track. After 10 microseconds, the laser beam passes on and the surface of the wafer cools back to ambient temperature.

 

2D Ray tracing Performance (180000 User Defined Rays)

No. of Processors Time (min) Speed Improvement
1 processor 66.0 min
2 processors 40.7 min 1.62
3 processors 27.4 min 2.4
4 processors 21.6 min 3.05
5 processors 18.6 min 3.55
6 processors 16.5 min 4
7 processors 15.6 min 4.23
8 processors 14.5 min 4.55

Rev. 110113_06