Electrically addressable tungsten doped phase change device in a through pixel configuration

In this paper, we propose and demonstrate electrical switching of a 4% tungsten-doped Ge 2 Sb 2 Te 5 (W-GST) pixel in a lateral configuration without the need for an auxiliary resistive heater. The phase transition between an amorphous and poly-crystalline state is achieved by Joule heating directly...

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Bibliographic Details
Published in:Optical materials express 2023-04, Vol.13 (4), p.1131
Main Authors: Burrow, Joshua A., Lawandi, Roseanna G., Sarangan, Andrew, Agha, Imad
Format: Article
Language:English
Subjects:
Actuation
Amorphization
Amplitude modulation
Configurations
Crystallization
Electric potential
Finite element method
Identification methods
Light sources
Materials failure
Ohmic dissipation
Optical reflection
Parameter identification
Phase change
Phase transitions
Pixels
Pulse duration
Resistance heating
Segregation process
Spatial light modulators
Switching
Temperature profiles
Tungsten
Voltage
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Summary:In this paper, we propose and demonstrate electrical switching of a 4% tungsten-doped Ge 2 Sb 2 Te 5 (W-GST) pixel in a lateral configuration without the need for an auxiliary resistive heater. The phase transition between an amorphous and poly-crystalline state is achieved by Joule heating directly through the 4 μ m × 4 μ m × 350 nm active volume of the chalcogenide phase change pixel. While undoped GST would be challenging to switch in a lateral configuration due to very large resistance in the amorphous state, W-GST allows for switching at reasonable voltage levels. The pixel temperature profile is simulated using finite element analysis methods to identify the pulse parameters required for a successful electrical actuation. Experimentally, a 1550 nm light source is used for in-situ optical reflection measurements in order to verify the crystallization and re-amorphization of the pixel. As a result of the W doping, we identify volatile and non-volatile regimes with respect to bias voltage and pulse width during crystallization. During amorphization, we observe irreversible material failure after one complete cycle using in-situ optical monitoring, which can be attributed to a migration or segregation process. These results provide a promising path toward electrically addressed devices that are suitable for optical applications requiring amplitude modulation in a reflective geometry, such as spatial light modulators.
ISSN:2159-3930
2159-3930
DOI:10.1364/OME.486073