Group III nitride semiconductor device and manufacturing method thereof

Abstract

The invention discloses a Group III nitride semiconductor device and a manufacturing method thereof. The group III nitride semiconductor device includes a nitride semiconductor layer and a passivation layer grown on a substrate, and also includes a source and a drain and a gate between the source and the drain. Wherein, the above-mentioned nitride semiconductor layer includes a nitride nucleation layer, a nitride buffer layer, a nitride channel layer, and a nitride barrier layer; the above-mentioned passivation layer is etched in the gate region to expose the nitride barrier layer , forming grooves at the gate. In the present invention, a composite dielectric layer is used between the nitride barrier layer and the gate metal layer, including a combined structure of a nitride dielectric layer, an oxynitride dielectric layer and an oxide dielectric layer sequentially formed from the direction of the substrate. The composite dielectric layer structure does not cause an increase in the interface state density, and compared with the traditional III-nitride semiconductor device with a single-layer oxide dielectric layer, it can simultaneously reduce the leakage and current collapse effects of the semiconductor device.

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...

AI Technical Summary

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

Images