Speaker
Description
The University of Western Australia (UWA) has established the use of Reactive Ion Etching (RIE) for n-on-p junction formation for high performance infrared imaging arrays made from Mercury Cadmium Telluride (MCT). A comprehensive understanding of RIE-induced effects on device parameters and the role of defects remains crucial for developing ultra-high quantum efficiency IR sensors and extending their operating temperatures. RIE is uniquely positioned to fabricate high quality n-on-p photodiodes through the conversion of p-type material into a highly doped n-type material caused by the diffusion of Hg atoms from the etched surface generating electrically active defects.
This work will present high resolution EBIC profiles of both mid-wave and long-wave MCT detailing the different responses to RIE parameters from the two compositions. The long-wave MBE grown sample has been patterned with meta-structures, RIE etched crosses, with the aim to increase longwave absorption beyond the as grown MCT limit and EBIC measurements were then used to identify the extent of the conversion process induced by the etching process. Comparative measurements of low and high electron penetration depth were generated using two different acceleration voltages to provide comprehensive examination of the unit cell, separating the surface/substrate effects. Simulations in Sentaurus TCAD were then used to compare the expected EBIC response from a completely n type sample to a sample with lateral n+ region diffusion. The measured signal only became apparent when the n+ region was introduced, verifying its effect on the signal and existence. The mid-wave LPE grown sample has been used to conduct a study of the depth and lateral extension the p-to-n type converted region as a function of temperature during RIE etching. High resolution cross-sectional imaging of the junction will be presented along with simulations confirming the device structure extracted.
| I am the presenting author | Yes |
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