Semiconductor substrates and semiconductor components

Abstract

The present invention is a semiconductor substrate comprising: a substrate; a buffer layer on the substrate; a high-resistance layer composed of a nitride-based semiconductor on the buffer layer and containing a transition metal and carbon; and a channel layer , which is composed of a nitride-based semiconductor on the high-resistance layer; the semiconductor substrate is characterized in that the high-resistance layer has a reduction layer, the reduction layer is adjacent to the channel layer, and the transition metal The concentration decreases from the buffer layer side toward the channel layer side; and the decrease rate of the carbon concentration decrease toward the channel layer is greater than the decrease rate of the transition metal concentration toward the channel layer. As a result, a semiconductor substrate capable of increasing the resistance of the channel layer side region of the high resistance layer while reducing the carbon concentration and the transition metal concentration in the channel layer is provided.

Description

technical field [0001] The invention relates to a semiconductor substrate and a semiconductor element, and the semiconductor element is manufactured using the semiconductor substrate. Background technique [0002] Semiconductor substrates using nitride semiconductors have been used in power devices and the like that operate at high frequency and high output. In particular, high electron mobility transistors (High Electron Mobility Transistor, HEMT) etc. are known as power elements suitable for amplification in high frequency bands such as microwaves, submillimeter waves, and millimeter waves. [0003] As a semiconductor substrate using a nitride semiconductor, there is known a semiconductor substrate in which a buffer layer, a GaN (gallium nitride) layer, and a resistor made of AlGaN (aluminum gallium nitride) are formed on a Si (silicon) substrate. Barrier layers are formed by stacking layers in sequence. [0004] In the lower layer (high resistance layer) of the GaN laye...

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Problems solved by technology

[0005] On the other hand, if the upper layer of the GaN layer functions as a channel layer and forms an energy level for trapping carriers, it may cause a decrease in mobility or current collapse due to scattering of impurities (reproducibility of output current characteristics deteriorates). phenomenon), it is necessary to sufficiently reduce the concentration of carbon, etc. (see Patent Documents 1 to 3)

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