Monolithic integration techniques for fabricating photodetectors with transistors on same substrate

摘要

Examples of the various techniques introduced here include, but not limited to, a mesa height adjustment approach during shallow trench isolation formation, a transistor via first approach, and a multiple absorption layer approach. As described further below, the techniques introduced herein include a variety of aspects that can individually and/or collectively resolve or mitigate one or more traditional limitations involved with manufacturing PDs and transistors on the same substrate, such as above discussed reliability, performance, and process temperature issues.

主权项

1. A method for fabricating a photodetector and a transistor on a same semiconductor substrate, the method comprising:
(1) on a semiconductor substrate, epitaxially growing a first layer of light absorption material of the photodetector over an area where the photodetector is to be formed; (2) after said growing the first layer of light absorption material, forming at least one layer of metallic contact plugs for the transistor; and (3) after said forming at least one layer of metallic contact plugs, forming a second layer of light absorption material of the photodetector, wherein the second layer of light absorption material is formed atop the first layer of the light absorption material, such that the two layers of light absorption material, having a substantially same material, form a single light absorption region for the photodetector, wherein the first layer and second layers of light absorption material are formed by using separate lithography processes, and wherein the separate lithography processes leave a sidewall misalignment on a structure that constitutes the single light absorption region.