Fabrication method for fused multi-layer amorphous selenium sensor
View Patent ↗A sensor including a layer of amorphous selenium (a-Se) and at least one charge blocking layer is formed by depositing the charge blocking layer over a substrate prior to depositing the amorphous selenium, enabling the charge blocking layer to be formed at elevated temperatures. Such a process is not limited by the crystallization temperature of a-Se, resulting in the formation of an efficient charge blocking layer, which enables improved signal amplification of the resulting device. The sensor can be fabricated by forming first and second amorphous selenium layers over separate substrates, and then fusing the a-Se layers at a relatively low temperature.
1 . A method of fabricating a sensor, comprising:
forming a first charge blocking layer over a first substrate;
forming a first layer of amorphous selenium over the first charge blocking layer;
forming a second charge blocking layer over a second substrate;
forming a second layer of amorphous selenium over the second charge blocking layer;
contacting the first layer of amorphous selenium with the second layer of amorphous selenium to form a multi-layer structure;
heating the multi-layer structure to fuse the first layer of amorphous selenium to the second layer of amorphous selenium.
2 . The method of claim 1 , wherein the first charge blocking layer and the second charge blocking layer each comprise an organic polymer.
3 . The method of claim 1 , wherein the first charge blocking layer and the second charge blocking layer are formed by physical vapor deposition, chemical vapor deposition or solution-based deposition.
4 . The method of claim 1 , wherein the first substrate comprises an electronic readout.
5 . The method of claim 1 , wherein the first charge blocking layer is formed over a pixel electrode.
6 . The method of claim 1 , wherein a thickness of the first layer of amorphous selenium is less than a thickness of the second layer of amorphous selenium.
7 . The method of claim 1 , wherein at least one of the first layer of amorphous selenium and the second layer of amorphous selenium comprises doped amorphous selenium.
8 . The method of claim 1 , wherein the second substrate comprises electroded glass or a scintillator.
9 . The method of claim 1 , wherein at least one of the first substrate and the second substrate is a flexible substrate.
10 . The method of claim 1 , further comprising forming a high voltage electrode over the second substrate prior to forming the second charge blocking layer.
11 . The method of claim 1 , wherein the multi-layer structure is heated to a temperature between 35° C. and 60° C. to fuse the amorphous selenium layers.
12 . The method of claim 1 , further comprising applying a compressive force to the multi-layer structure during the heating.
13 . The method of claim 1 , wherein heating the multi-layer structure to fuse the first and second layers of amorphous selenium is performed under vacuum.
14 . The method of claim 1 , wherein the fused layers of amorphous selenium are free of pores.
15 . A method of fabricating a sensor, comprising:
forming a charge blocking layer over a substrate;
forming a layer of amorphous selenium over the charge blocking layer; and
heating the layer of amorphous selenium to fuse the layer of amorphous selenium to the charge blocking layer.
16 . The method of claim 15 , wherein the substrate is a flexible substrate.
17 . The method of claim 15 , wherein the charge blocking layer is formed by physical vapor deposition or chemical vapor deposition at a temperature of at least 200° C.
18 . The method of claim 15 , wherein the layer of amorphous selenium is heated to a temperature between 35° C. and 60° C. to fuse the layer of amorphous selenium to the charge blocking layer.