Method for preventing transverse diffusion of ohmic contact aluminum in GaN-based device

Abstract

The invention discloses a method for preventing transverse diffusion of ohmic contact aluminum in a GaN-based device. Ohmic contact aluminum is deposited in pores of a heat-resisting silicon nitride medium, transverse diffusion of ohmic contact aluminum is blocked by the heat-resisting silicon nitride medium, surface protection for ohmic alloy is further realized, and interface pollution and interface state are reduced. The method comprises: the heat-resisting silicon nitride medium grows on the surface of an epitaxial material; pores are formed in the high-temperature silicon nitride medium covering the area of an ohmic contact metal pattern; ohmic contact metal is evaporated in the formed pores of the silicon nitride medium to form metal stacking, wherein the upper surface of the silicon nitride medium is not lower than the upper surface of a stacked metal aluminum layer in the area of the formed pores. The method solves the problem of aluminum transverse diffusion in ohmic contact preparation of the GaN-based device, avoids the risk that the device performance is degraded due to a polluted material surface in a high-temperature alloy technology, further realizes surface protection of ohmic alloy, and reduces interface pollution and interface state.

Description

technical field [0001] The invention relates to the technical field of ohmic contact and passivation technology in GaN-based devices, in particular to a method for preventing lateral diffusion of aluminum elements in ohmic contacts in GaN-based devices. Background technique [0002] The ohmic contact metal system of mainstream GaN-based devices usually contains an aluminum metal layer. The purpose of introducing the aluminum metal layer is to reduce the resistivity of the ohmic contact. However, the latest research has found that aluminum is easy to diffuse laterally in high-temperature alloys, and oxidizes and deposits at high temperatures. On the surface of the epitaxial material, the surface state of the epitaxial material remains high, reducing device performance. [0003] In addition, considering the ultra-high temperature conditions of the alloy greater than 800°C, the silicon nitride dielectric grown at low temperature has a large thermal mismatch with the gallium nit...

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Problems solved by technology

[0005] In view of this, the main purpose of the present invention is to provide a method for preventing the lateral diffusion of ohmic contact aluminum elements in GaN-based devices, so as to solve the problem of lateral diffusion of aluminum elements in the preparation of ohmic contacts of GaN-based devices. Deposited in high temperature resistant silicon nitride dielectric holes, blocking the lateral diffusion of aluminum elements through the dielectric

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