Method and substrate for thick III-N epitaxy

Abstract

A method of manufacturing an III-N substrate includes bonding a Si substrate to a support substrate, the Si substrate having a (111) growth surface facing away from the support substrate, thinning the Si substrate at the (111) growth surface to a thickness of 100 [mu]m or less, and forming III-N material on the (111) growth surface of the Si substrate after the Si substrate is thinned. The support substrate has a coefficient of thermal expansion more closely matched to that of the III-N material than the Si substrate. Other methods of manufacturing an III-N substrate are disclosed, as well as the corresponding wafer structures.

Description

technical field [0001] This application relates to III-N wafer structures, and more particularly to forming thick III-N wafer structures. Background technique [0002] As a semiconductor material for making devices, GaN offers several superior properties over Si, such as lower threshold voltage, lower on-state resistance (Rdson), lower parasitic capacitance, lower gate resistance and better FOM (figure of merit), resulting in a great performance and size advantage over Si. With such advantages as obvious motivators, extensive efforts are underway in the semiconductor industry to improve the crystal quality of GaN. For example, GaN typically has a high defect density attributable to slip lines caused by a lattice mismatch between the growth substrate and GaN epitaxy (e.g. -17% in the case of GaN on Si(111)) . In many cases (eg power devices, such as GaN-based HEMTs (High Electron Mobility Transistors)), reducing the defect density caused by slip lines yields improvements i...

AI Technical Summary

Problems solved by technology

[0003] However, the maximum thickness of GaN grown on Si is limited by the difference in the coefficient of thermal expansion (CTE) between the two materials

Images