Design and fabrication of single grain TFTs and lateral photodiodes for low dose X-ray detection

Design and fabrication of single grain TFTs and lateral photodiodes for low dose X-ray detection

Arslan, A.
Ishihara, R.
Derakhshandeh, J.
Beenakker, C.I.M.

Electrical Engineering, Mathematics and Computer Science

Microelectronics

2011-03-16

Design, fabrication and measurement results of single grain (SG) lateral PIN photodiodes and SG thin film transistors (TFT) are reported in this paper. Devices were developed to be used in indirect X-ray image sensor pixel design. We have controlled position of 6 ?m x 6 ?m silicon grains with excimer-laser crystallization of a-Si film. Lateral PIN photodiode (PD) arrays were designed inside the single grain with 1 ?m, 1.5 ?m and 2 ?m intrinsic region length and 4 ?m width. The gate length and the width of the fabricated TFTs are 1.5 ?m and 4 ?m, respectively. Devices were fabricated using a-Si, SOI and crystalline silicon layers and electrical measurement results were compared. 100 ?m x 100 ?m sizes SG-photodiodes have dark and saturation currents on the order of 0.1 nA and 10 nA resulting in a light sensitivity of 200 with an exposure of white light. Fabricated NMOS and PMOS TFTs inside the grains have field effect mobility of 526 cm2/Vs and 253 cm2/Vs, respectively.

X-ray, thin-film-transistor (TFT), single grain, large area detection, image sensor, ?-Czochralski process

http://resolver.tudelft.nl/uuid:66621333-dc12-458f-8536-1e733fe71eb8

https://doi.org/10.1117/12.877959

SPIE

0277-786X

https://doi.org/10.1117/12.877959

Proceedings of SPIE, 2011 vol. 7961

Institutional Repository

conference paper

(c)2011 Arslan, A., Ishihara, R., Derakhshandeh, J., Beenakker, C.I.M.