GaN side wall insulated gate fin-type high-electron mobility transistor and manufacturing method thereof

Abstract

The invention relates to a GaN side wall insulated gate fin-type high-electron mobility transistor and manufacturing method thereof. A transistor structure of the invention orderly comprises a substrate, a buffer layer, a barrier layer and a passivation layer from bottom to top; a source electrode is arranged at one end above the barrier layer, and a drain electrode is arranged at another end above the barrier layer; the passivation layer is arranged above the barrier layer between the source electrode and the drain electrode; and a groove is formed in the passivation layer; the high-electron mobility transistor is characterized by further comprising a GaN based three-dimensional fin and a gate electrode, and an insulating medium is arranged on a side wall of the GaN based three-dimensional fin; a part of the gate electrode is covered on the barrier layer in the groove to form the Schottky contact; another part of the gate electrode is covered on the insulating medium on the side wall of the GaN based three-dimensional fin to form an insulated gate structure. The GaN based three-dimensional fin type device has the advantages of being small in gate electric leakage, high in output current, good in gate-control capacity and high in frequency characteristics, and can be used for a large-power microwave power device.

Description

technical field [0001] The invention belongs to the technical field of semiconductor device preparation, in particular to a GaN sidewall insulating gate fin type high electron mobility transistor and a manufacturing method thereof. [0002] technical background [0003] The third-generation semiconductor GaN-based high electron mobility transistor (HEMT) has the advantages of high output power density, wide bandgap, high saturation speed, high breakdown field strength, etc. Mainstream technology has strongly promoted the development of wireless base stations, satellite communications, medical care, radar, green energy and other fields. By shrinking the device size vertically and laterally, the frequency of GaN planar devices continues to increase. However, due to the limitation of the thickness of the barrier layer, further shrinking the gate length will lead to weakened gate electrostatic control ability, increased device leakage, deterioration of short channel effects (SCE...

AI Technical Summary

Problems solved by technology

[0005] However, due to the direct contact between the gate metal and the sidewall two-dimensional electron gas channel (2DEG), the Schottky barrier is lower, and the dry etching process inevitably damages the sidewall, making the gate leakage of FinFET devices increases, the maximum driving gate voltage decreases, and finally leads to lower driving current of the device (see the literature Shenghou Liu et al., Enhancement-Mode Operation of Nanochannel Array (NCA) AlGaN / GaN HEMTs, IEEE Electron DeviceLett., vol.33, no.3,pp.354-356,2012)

Although the leakage problem can be solved by an insulated gate structure (MIS), the gate dielectric will also cover the upper part of the barrier layer, so that the top and both sides of the three-dimensional fins form a MIS structure, but this increases the top gate and channel. The control ability of the top gate is greatly reduced, and the frequency characteristics are degraded, which ultimately makes it difficult to fully utilize the advantages of the FinFET structure.

[0006] A Chinese patent application discloses a multi-channel fin structure AlGaN / GaN high electron mobility transistor structure and manufacturing method, which mainly solves the problems of poor gate control ability of existing multi-channel devices and low current of FinFET devices

[0007] A Chinese patent application discloses a T-gate N-plane GaN / AlGaN fin-type high electron mobility transistor, which mainly solves the problems of low maximum oscillation frequency, large ohmic contact resistance and serious short channel effect of existing microwave power devices

[0008] Although the above two solutions respectively solve the problems of GaN multi-channel and N-surface structure gate control capability and output current, there are still obvious deficiencies: the traditional GaN-based fin structure is mainly used, and the gates on both sides of the fin are directly connected to the side 2DEG contact at the wall, such as "N-plane GaN-based fin-type high electron mobility transistor and its fabrication method" figure 1 As shown, this will have two adverse effects, one is the low side gate Schottky barrier height, which will lead to large gate leakage; the other is that the side gate of the Schottky contact will introduce large parasitic capacitance, reducing the device frequency characteristic

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