Oxygen inserted si-layer in vertical trench power device

Abstract

The invention discloses an oxygen inserted SI-layer in a vertical trench power device. A semiconductor device includes a gate trench extending into a Si substrate, a body region in the Si substrate adjacent the gate trench, a source region in the Si substrate above the body region, a contact trench extending into the Si substrate and filled with an electrically conductive material which contacts the source region at a sidewall of the contact trench and a highly doped body contact region at a bottom of the contact trench, a diffusion barrier structure formed along the sidewall of the gate trench, the diffusion barrier structure comprising alternating layers of Si and oxygen-doped Si and a Si capping layer on the alternating layers of Si and oxygen-doped Si, and a channel region formed in the Si capping layer and which vertically extends along the sidewall of the gate trench. Corresponding methods of manufacture are also described.

Description

Background technique [0001] As the dimensions of trench-based transistors shrink, the effect of highly doped source / body contacts on the net body doping near the channel region becomes more important. For wider lateral distribution of source / body contact diffusion with 2–3 orders of magnitude higher doping levels compared to bulk doping, the Vth (threshold voltage) and RonA (on-state resistance) of the device increase. Increasing the distance between the source / body contacts and the channel region causes depletion of the body at high drain voltages, which can lead to high DIBL (drain-induced barrier lowering). Furthermore, the process window variation of both trench width and contact width as well as contact misalignment must become smaller to avoid these adverse effects (higher Vth, higher RonA and higher DIBL). [0002] Therefore, better control over the lateral out-diffusion of source / body contact doping is desirable. Contents of the invention [0003] According to an e...

AI Technical Summary

Problems solved by technology

Increasing the distance between the source / body contact and the channel region causes depletion of the body at high drain voltages, which can lead to high DIBL (drain-induced barrier lowering)

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