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Study of UMSM photodetectors fabrication technique by silicic acid added in TMAH solution
Author(s)
Suttijalern, Kamonwan
Prabket, Jirawat
Niemcharoen, Surasak
Date Issued
January 1, 2018
Type
Conference Paper
Abstract
This paper presents about the U-shape metal-semiconductor-metal (UMSM) photodetectors fabrication on Al/n-Si/Al. This technique performs by using anisotropic wet etching with the depth of U-shape about 4 – 5 µm. In the experiment, 5 wt % of Tetramethylammonium hydroxide (TMAH) were mixed with 30 – 38 g/l silicic acid (H4SiO4) at 80°C. The result found that the UMSM photodetectors fabrication can increase the light detecting area about 1.73 times when compared with planar structure. Moreover, the added of silicic acid in TMAH solution were decrease Al and silicon dioxide etch rates. The effective condition is 5 wt % TMAH mixed with 34 g/l silicic acid that provided lowest Al and SiO2 etch rates. For the light responsibility analysis at 25,000 Lux, the UMSM structure showed the photocurrent higher than planar structure about 2.4 times. This study found that, the optimal volume of silicic acid that added in TMAH solution can reduce the Al and SiO2 etch rates. This condition should be suitable for photodetectors fabrication.
Citation
Lecture Notes in Engineering and Computer Science, 2, 2018