Method of fabricating a semiconductor on insulator device having a frontside substrate contact

Abstract

A method of forming a substrate contact in a semiconductor device, comprising the steps of providing a semiconductor base substrate (2) having a buried oxide (BOX) layer (4) and a thin active semiconductor layer (103) on the BOX layer (4), forming a trench (104) in the active semiconductor layer (103) and the Box layer (4) to the semiconductor base substrate (2) below, and then depositing anotheractive semiconductor (epitoxial) layer (6) over the remaining active semiconductor layer (103) and in the trench (104) to create the substrate contact. The trench (104) is etched at a location on thewafer corresponding to a scribe lane (106).

Description

technical field [0001] The present invention relates to a method of fabricating a semiconductor-on-insulator (SOI) device having a front-side substrate contact. Background technique [0002] It is generally desirable for active semiconductor devices to be completely electrically isolated from the underlying semiconductor substrate and adjacent active devices. [0003] Vertical isolation of active devices is typically achieved using a semiconductor-on-insulator (SOI) substrate, referred to figure 1 , comprising a base semiconductor (typically silicon) substrate 2 having a buried insulator (typically silicon oxide) or BOX layer 4 formed on its upper surface, and a layer 4 formed on said BOX layer 4 The active junction semiconductor (typically silicon) layer 6. Active devices (transistors) are fabricated in the active semiconductor layer 6 on top of said insulating layer 4 . [0004] In many applications, the base semiconductor substrate 2 needs to be grounded or grounded, a...

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Problems solved by technology

However, a major disadvantage of this option is the deep contact etch, since it is mostly performed at the end of the process flow

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