III-nitride semiconductor device and manufacturing method for same

Abstract

The invention discloses an III-nitride semiconductor device and a manufacturing method for the same. The III-nitride semiconductor device comprises a nitride semiconductor layer, a passivation layer, a source, a drain and a gate, wherein the nitride semiconductor layer and the passivation layer are grown on a substrate; the gate is positioned between the source and the drain; the nitride semiconductor layer comprises a nitride nucleating layer, a nitride buffer layer, a nitride trench layer and a nitride potential barrier layer; the passivation layer is etched in a gate area until the nitride potential barrier layer is exposed, and a groove is formed in the gate. According to the device and the method, a combined structure of a composite dielectric layer is adopted between the nitride potential barrier layer and a gate metal layer, and the composite dielectric layer comprises a nitride dielectric layer, an oxynitride dielectric layer and an oxide dielectric layer, which are sequentially formed from the substrate, so that the increase of interface state density is avoided; compared with a conventional III-nitride semiconductor device with a single oxide dielectric layer, the III-nitride semiconductor device with the composite dielectric layer has the advantage that the electric leakage and current collapse effects of the semiconductor device can be simultaneously reduced.

Description

technical field [0001] The invention relates to the technical field of microelectronics, in particular to a Group III nitride semiconductor device and a manufacturing method thereof. Background technique [0002] Group III nitride semiconductors have the characteristics of wide band gap, high dielectric breakdown field strength and high electron saturation drift rate, which are suitable for manufacturing high-temperature, high-speed switching and high-power electronic devices. In a nitride field effect transistor, a large amount of charge is generated in the channel layer by piezoelectric polarization and spontaneous polarization. Since the source of the two-dimensional electron gas is the ionization of the donor surface state on the nitride surface, the current density of the nitride transistor is extremely sensitive to the surface state, and the existence of the surface state can easily cause the current collapse effect. [0003] Gallium nitride-based field effect transis...

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Problems solved by technology

However, in the insulated gate field effect transistor manufactured by this method, there is a high density of interface states between the dielectric layer and the nitride semiconductor, which can cause serious current collapse effects, which is a big unresolved problem, such as figure 1 shown

Moreover, the insulating dielectric layer and the nitride semiconductor layer (such as Al 2 o 3 When there is a higher interface state between AlGaN and AlGaN), under forward bias, the charging and discharging of the interface state at the edge of the AlGaN conduction band will cause the hysteresis effect of the C-V curve of the device, that is, the forward curve and the reverse There will be a large degree of misalignment in the curves, such as figure 2 shown

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