Groove Gamma gate transistor with high electron mobility and preparing method thereof

Abstract

The invention discloses a groove gamma gate transistor with high electron mobility and a fabrication method thereof. The transistor comprises, from bottom to top, a substrate (1), a transition layer (2), a barrier layer (3), a source electrode (4), a drain electrode (5), a passivation layer (7), a gamma gate (9) and a protection layer (11); a first groove (6) is opened on the barrier layer (3), a second groove (8) is opened on the passivation layer (7), wherein, n floating field plates (10) are deposited on the passivation layer (7) (n is not less than 1), and the floating field plates and the gamma-gate form a composite gate field plate structure. All the floating field plates have the same size and are mutually independent, and the distance between two adjacent floating field plates increases based on the number of the floating field plates arranged along the direction from the gamma gate to the drain electrode. The n floating field plates are in a floating state and are completed together with the gamma gate by one-time process. The groove gamma gate transistor has the advantages of high yield, good frequency characteristic and high output power, and the groove gamma gate transistor and the fabrication method can be used for fabricating high-frequency high power devices based on III-V group compound semiconductor heterojunction structure.

Description

technical field [0001] The invention belongs to the technical field of microelectronics, and relates to semiconductor devices, in particular to a grooved Γ-gate high electron mobility transistor based on the heterojunction structure of III-V compound semiconductor materials, which can be used as a microwave, millimeter wave communication system and radar system. basic device. technical background [0002] As is well known in the industry, semiconductor materials composed of group III elements and group V elements, that is, group III-V compound semiconductor materials, such as gallium nitride (GaN)-based, gallium arsenide (GaAs)-based, indium phosphide (InP)-based And other semiconductor materials, their bandgap widths are often quite different, so people usually use these III-V compound semiconductor materials to form various heterojunction structures. Due to the large difference in the band gap of III-V compound semiconductor materials on both sides of the heterojunction i...

AI Technical Summary

Problems solved by technology

However, the manufacturing process of the high electron mobility transistor using the stacked field plate structure is relatively complicated. Each additional layer of field plate requires additional process steps such as photolithography, metal deposition, insulating dielectric material deposition, stripping, and cleaning. To make the insulating dielectric material deposited under the field plates of each layer have an appropriate thickness, cumbersome process debugging must be carried out, thus greatly increasing the difficulty of device manufacturing and reducing the yield of devices

Another issue worthy of people's attention is that all high electron mobility transistors using a gate field plate structure will generate additional capacitance between the gate field plate and the two-dimensional electron gas channel, and this additional capacitance will be superimposed into the gate and the gate of the device. In the feedback capacitance between the drains, the feedback capacitance of the device increases, resulting in a certain attenuation of the power characteristics and frequency characteristics of the device.

In addition, the increase of the feedback capacitance of the device will weaken the isolation between the input and output of the device and reduce the stability of the device

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