Method for improving the performance of gallium nitride based field effect transistor

Abstract

The invention relates to the technical field of production of wide bandgap semiconductor materials and devices and discloses a method for improving the performance of a GaN-based field-effect transistor, the method comprises: mixed pre-treatment solution is adopted to carry out the surface pre-treatment of the surface of a device before the passivation of the GaN-based field-effect transistor during the production process of the GaN-based field-effect transistor, then a compound dielectric layer of silicon nitride and oxygen-rich silicon nitride is deposited on the surface of the device afterthe surface pre-treatment, and the GaN-based field-effect transistor is passivated. The use of the method can solve a surface original oxide layer which is existed on the surface of AlGaN for a long time, eliminate the AlGaN surface state which is induced by the surface oxide layer, solve the surface state existing in an AlGaN and silicon nitride interface, the current collapse effect which is induced by the surface original oxide layer and the significant increase of the reverse gate leakage current caused by the conventional passivation and improve the stability and the reliability of GaN-based HEMT.

Description

technical field [0001] The invention relates to the technical field of manufacturing wide bandgap semiconductor material devices, in particular to a method for improving the performance of gallium nitride-based field effect transistors. Background technique [0002] Gallium nitride (GaN), as the third-generation wide-bandgap semiconductor material, has a large bandgap (3.4eV), a high breakdown voltage (3.3MV / cm), and a high two-dimensional electron gas concentration (>10 13 cm 2 ), high velocity of saturated electrons (2.8×10 7 cm / s) and other characteristics have received extensive attention internationally. At present, the high-frequency, high-voltage, high-temperature and high-power characteristics of GaN-based field-effect transistor (AlGaN / GaN HEMT) devices make them have great application prospects in microwave power devices. [0003] Although the performance of aluminum gallium nitride / gallium nitride (AlGaN / GaN) HEMT devices has made great progress in recent ye...

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Problems solved by technology

[0014] 1. There are surface states and original oxide layers on the surface of AlGaN, and the concentration of surface states is not eliminated or reduced due to silicon nitride passivation. PECVD deposited silicon nitride is passivated, and the surface states and surface states that exist at the interface between AlGaN and silicon nitride The original oxide layer, so that there is still a certain degree of current collapse effect

[0015] 2. The original oxide layer existing on the surface of AlGaN makes the electric field at the edge of the gate metal increase significantly after silicon nitride passivation, so that the gate reverse leakage current increases to a large extent after silicon nitride passivation. This will seriously affect the breakdown voltage of the device and may reduce the power gain of the device to a large extent

[0016] 3. The original oxide layer and surface state existing at the interface of AlGaN and silicon nitride after passivation are characterized by instability, which seriously affects the stability and reliability of the device under the action of long-term high-frequency high-electric field stress

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