Enhanced GaN-based MIS-HEMT device and preparation method thereof

Abstract

The invention relates to an enhanced GaN-based MIS-HEMT device and a preparation method thereof. In the MIS-HEMT device, a concave AlGaN barrier layer is arranged on the basis of a thin AlGaN barrierlayer, so that the channel mobility is improved, and the on resistance is improved. On the basis, an electron beam evaporation (EBE) method is adopted to grow a mask layer and is combined with an SAGmethod, compared with a PECVD mask used in a conventional process, the adoption of the EBE for growing the mask completely eliminates plasma damage in the mask technology, and damage-free crystal lattices are reserved for a thin AlGaN / GaN heterojunction. Meanwhile, the Al component of the AlGaN thin barrier layer is different from the Al component of the concave AlGaN barrier layer, and the threshold voltage and the channel electron mobility are further improved. In addition, a gate dielectric layer in the device is formed by stacking three oxide materials with different dielectric constants,the thickness of the dielectric layer is increased to ensure a certain threshold voltage, and the gate capacitance is increased by means of increasing the dielectric constant, so that the transconductance value is prevented from being too low.

Description

technical field [0001] The invention relates to the field of microelectronic technology, in particular to an enhanced GaN-based MIS-HEMT device and a preparation method thereof. Background technique [0002] GaN is a wide-bandgap semiconductor material. Because of its high saturation electron drift velocity, breakdown electric field strength, and high thermal conductivity, it can also form a heterojunction with AlGaN, and form a high-concentration, high-mobility secondary at the interface of the structure. Dimensional electron gas. Therefore, using GaN as a high-power, high-frequency device can make the on-resistance of the device small and the switching speed fast, and it has been widely used in the fields of wireless communication, radar and aerospace. [0003] In the application field of high-power transistors, GaN-based HEMT devices play a very important role. Due to the presence of strong polarized charges in the AlGaN / GaN heterojunction, it is difficult to fabricate ...

AI Technical Summary

Problems solved by technology

However, this method requires very strict etching conditions to control the recessing process

A silicon dioxide mask grown by PECVD introduces plasma-based damage in the active region, resulting in lower mobility

At the same time, there is a problem of lower channel mobility

[0004] After the gate dielectric is introduced, the gate capacitance of the device becomes smaller, which will lead to weakened gate control capability and reduced transconductance

Therefore, it is necessary to select a material with a larger dielectric constant and a smaller dielectric thickness as the gate dielectric, but this will lead to a decrease in the threshold voltage of the device, and the threshold voltage will increase with the increase in the thickness of the gate dielectric.

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