Compound semiconductor device

Abstract

The invention provides a compound semiconductor device with a simple structure, capable of suppressing impurity diffusion, improving characteristics and stabilizing production. A buffer layer (2), a first carrier supply layer (3), a first spacer layer (4), a channel layer (5), a second spacer layer (6), a second carrier supply layer (7), and a contact layer (9) are provided in order on a substrate (1), wherein the first carrier supply layer (3) is a uniformly doped layer in which an impurity is uniformly doped, the second carrier supply layer (7) is a planar doped layer in which an impurity is locally doped, and no Al mixed crystal layer having higher resistance values than the first and second spacer layers (4, 6) is provided between the buffer layer (2) and the first spacer layer (4) and between the second spacer layer (6) and the contact layer (9).

Description

Technical field [0001] The present invention relates to compound semiconductor devices such as high electron mobility transistors. Background technique [0002] High Electron Mobility Transistor (HEMT: High Electron Mobility Transistor) exerts its excellent high frequency characteristics and is used in amplifiers such as receiving antennas for satellite broadcasting and millimeter wave radars for vehicles. Regarding the epitaxial structure of HEMT that has been put into practical use in recent years, in order to supply carriers with high concentration and efficiency to the channel layer, which is the carrier transfer layer, double-doped HEMT has become the mainstream. This double-doped HEMT is not only on the channel layer On the lower side, it also has a carrier supply layer. [0003] As the carrier supply layer of the double-doped HEMT, a uniformly doped supply layer is used. The uniformly doped supply layer has a desired thickness and is uniformly doped with impurities. In add...

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Problems solved by technology

[0008] In the technique of lowering the temperature of epitaxial growth, in particular, impurities such as oxygen are likely to be mixed into the layer containing Al, which may lead to deterioration of reliability.

In addition, in the technology of adding In to the layer near the planar doped layer, the epitaxial structure and growth process become complicated, so it is difficult to stably produce

In addition, if an Al mixed crystal layer is provided, it becomes a resistive layer, and the source series resistance increases, so there is a problem that high-frequency characteristics deteriorate and mobility decreases.

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