ELECTRONIC DEVICE USING GROUP III NITRIDE SEMICONDUCTOR AND ITS FABRICATION METHOD AND AN EPITAXIAL MULTI-LAYER WAFER FOR MAKING IT

摘要

The present invention discloses an electronic device using a group III nitride substrate fabricated via the ammonothermal method. By utilizing the high-electron concentration of ammonothermally grown substrates having the dislocation density less than 105 cm−2, combined with a high-purity active layer of Ga1-x-yAlxInyN (0≦x≦1, 0≦y≦1) grown by a vapor phase method, the device can attain high level of breakdown voltage as well as low on-resistance. To realize a good matching between the ammonothermally grown substrate and the high-purity active layer, a transition layer is optionally introduced. The active layer is thicker than a depletion region created by a device structure in the active layer.

主权项

1. An epitaxial multi-layer wafer for fabricating electronic devices comprising (i) a group III nitride substrate of Ga1-x1-y1Alx1Iny1N (0≦x1≦1, 0≦y1≦1) having a first side and a second side opposite to the first side and (ii) an active layer of Ga1-x2-y2Alx2Iny2N (0≦x2≦1, 0≦y2≦1) on the first side of the group III nitride substrate, wherein:
(a) a dislocation density of the group III nitride substrate is less than about 105 cm−2; (b) the group III nitride substrate is selected from the group consisting of (i) a group III nitride substrate having an electron concentration higher than about 1018 cm−3 and (ii) a group III nitride substrate having an oxygen concentration higher than about 1018 cm−3; (c) the group III nitride substrate is fabricated from a bulk crystal of Ga1-x1-y1Alx1Iny1N (0≦x1≦1, 0≦y1≦1) grown in supercritical ammonia; (d) the active layer is an epitaxially deposited layer selected from the group consisting of (i) an active layer having an electron concentration lower than about 1018 cm−3 and (ii) an active layer having an oxygen concentration lower than about 1018 cm−3; (e) the active layer has a thickness sufficiently large that a depletion region which is formed in the active layer after fabricating the electronic device with a first electrode on the first side of the wafer and a second electrode on the second side of the wafer is outside of the substrate.