The Development of Compound Based Light-Addressable Ion Sensor with Back Side Light Source Array (II)

In the development of light addressable potential-metric sensors (LAPS), there is an evolution from the data received via single light source to the use of laser scanning in order to detect 2D information. However, more time is consumed and larger space is occupied due to the scanning process and measurement facility, respectively. In this project, by using of MOCVD system and double side epitaxial technique, we’d like to propose a compound semiconductor based 2D LAPS. On the backside 2D LED array is made, the front side is exhibited an electrolyte insulator semiconductor (EIS) structure, and so as to integrate both of them together. The proposed sensor will be equipped with a frequency modulator for the LED array driving circuit, which is able to quickly scan the pixel in a short period of time. Such design brings about an innovative idea regards compound 2D LAPS. (1). In the Summer of 2014, we had grown GaN LED and GaN EIS structure, both on Sapphire, separately. And then, by using the wafer bonding technology, EIS and 2D LED array were bonded backside to backside together. We had also design the driving circuit to drive a 4x4 prototype LED array in the same period. And the real time 2D pH surface was measured by GaN LAPS with blue LED array and presented already in Nov., 2014 IEDMS. (2). In the year of 2015, we will go further to focus our study on the double-sided GaN epitaxial growth (on the Sapphire or SiC substrates), so that EIS structure and LED 2D array may be fully integrated into one LAPS structure. In the second year progression, our team have to solve the back surface contamination problem during the MOCVD re-growth process. Then, we can grow EIS together with 2D LED array, and improve the light spots divergence problem which results in a low-resolution phenomenon. Next step onwards; we need to normalize the pH data variation which is due to the non-homogeneous epitaxial growth of 2D LED array. (3). In the year of 2016, our team will attempt to optimize the double-sided epitaxial growth combine with different heterogeneous (GaN/Sapphire/GaN, GaN/SiC) substrates. By incorporating data from the past two years, LAPS device will undergo a real time dynamic 2-D scanning, including signal optimization and sensing membrane selection.

Project ID:PB10408-5715
External Project ID:MOST104-2221-E182-038