Method for manufacturing gallium nitride base semiconductor photoelectric device

Abstract

The invention discloses a manufacture method of a gallium nitride-based semiconductor photoelectric device. A Ni / Au / Ti / Au metal layer is formed on an n type gallium nitride-based semiconductor layer by adopting a vaporizing or sputtering method in sequence, and an n electrode is formed in a stripping or chemical etching method; the 400 to 600 DEG C annealing treatment is performed to the n electrode in the atmosphere including oxygen, therefore causing the n electrode and the n type gallium nitride-based semiconductor layer form an alloy, in the n electrode, the Ni / Au / Ti metal layer is an ohm contact layer, and the Au metal layer at the top layer is taken as a welding cushion layer. Because the n electrode does not include Al with low melting point, the temperature of the annealing treatment is moderate, the original metallurgical phase structure of the electrode can be better maintained, thus the trouble brought to the subsequent capsulation is avoided; further more, the temperature of the annealing treatment is moderate, the heat treatment can be performed to the ohm contact layer and the welding cushion layer together, the degeneration and the hardening of the metal of the welding cushion layer are guaranteed not to be caused meanwhile the separating manufacture of the contact layer and the welding cushion layer is avoided, therefore the process is simplified, the finished product rate is improved, and the cost is reduced.

Description

technical field [0001] The invention relates to a manufacturing method of a semiconductor device, in particular to a manufacturing method of a gallium nitride-based semiconductor optoelectronic device which greatly simplifies the manufacturing process of the device, improves the yield and reduces the cost. Background technique [0002] Group III-V compound nitrides represented by GaN have become one of the hot spots in the research and development of compound semiconductors in recent years because of their superior properties; based on their large band gap, high electron saturation drift speed, and good thermal conductivity, etc. The characteristics are suitable for making high-frequency and high-power electronic devices; and using its wide direct bandgap to make short-wavelength visible light and ultraviolet light optoelectronic devices. [0003] In the manufacturing process of gallium nitride-based semiconductor devices, the ohmic contact layer in the n-electrode generally...

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Problems solved by technology

[0003] In the manufacturing process of gallium nitride-based semiconductor devices, the ohmic contact layer in the n-electrode generally adopts a Ti / Al (titanium / aluminum) double-layer metal structure, but the Ti / Al double-layer structure is easily oxidized and has poor thermal stability. Poor, under conventional device packaging conditions (for example: temperature 150°C, air atmosphere, duration 30 minutes), the contact resistance will increase, and the reliability of the device will deteriorate; for this reason, it is usually required to Afterwards, it is thermally annealed to form a thermally stable ohmic contact, and at the same time, in order to prevent the interdiffusion between the metal layer (such as Au) used as the pad and the ohmic contact layer from changing the contact properties, usually between the two A layer of high melting point metal material is inserted between them as a barrier layer

The product and its manufacturing method disclosed in the Chinese patent (name: GaN-based III-V compound semiconductor device and its manufacturing method, patent number: ZL00126376.5) are typical representatives of this manufacturing process. However, such manufacturing process, there are the following obvious problems: first, the surface of the electrode containing Ti / Al becomes very rough after heat treatment, which will bring great difficulties to the PR identification of the automatic wire bonding machine during the packaging process; secondly, In order to obtain a low-resistance ohmic contact between Ti / Al and n-type GaN-based materials, annealing is usually performed at a higher temperature (such as 750-950°C mentioned in Chinese patent ZL00126376.5), which will The pad metal layer (for example: gold or aluminum) will deteriorate and harden, making it difficult or even impossible to solder wires. Therefore, if this process is used, the Ti / Al contact layer and the pad metal layer need to be made separately in the actual manufacturing process. , to prevent the metal layer of the pad from undergoing high-temperature deterioration and hardening, but this requires at least two additional photolithography and coating processes. The increase in process complexity will not only cause a decrease in yield, but also increase production costs

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