A kind of mosfet device nitriding method

Abstract

The present invention provides a method for nitriding a MOSFET device, comprising nitriding the MOSFET device with nitrogen-containing gas, preferably the nitriding treatment is performed at a temperature of 1200-1500°C, preferably 1250-1450°C. According to the nitriding method of the power device provided by the present invention, nitrogen is used for nitriding at a high temperature during the oxidation process and / or after oxidation of the device, which simplifies the nitriding passivation gas system, avoids gate dielectric reliability and breakdown electric field strength The reduction of potential toxicity and poisonous gas leakage risk caused by nitriding gas is avoided, and the exhaust gas treatment system is simplified.

Description

technical field [0001] The invention relates to the field of power devices, in particular to a nitriding and passivation method for a MOSFET device. Background technique [0002] SiC material is currently the only one that can form SiO through thermal oxidation 2 The compound semiconductor of the film, which makes the manufacture and performance optimization of SiCMOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor, Metal-Oxide-Semiconductor Field-Effect Transistor) devices can learn from the mature Si process. However, SiC MOSFET devices suffer from low channel mobility, mainly due to the thermal oxidation of SiO 2 / SiC interface state density is too high. SiO 2 / SiC interface state traps mainly originate from near-interface defects in the oxide layer and SiO 2 Carbon residue at the / SiC interface. Since the SiC lattice contains carbon atoms, there are carbon dangling bonds or carbon clusters remaining at the interface after thermal oxidation. These interface st...

AI Technical Summary

Problems solved by technology

[0007] 1) Different gases need to be used for multi-step nitriding passivation, and the process is complicated;

[0008] 2) NO is a poisonous gas; N 2 The decomposition of O at high temperature will also produce toxic gas NO; NH 3 Flammable, Toxic, Irritant

Therefore, the annealing equipment has high sealing requirements, expensive equipment, and needs to be equipped with a complex tail gas treatment system, the process is dangerous and the process cost is high

[0009] 3) NO and N 2 O itself is oxidizing, and when N atoms are introduced at the interface, it will also oxidize SiO 2 The / SiC interface is further oxidized, resulting in the generation of new interface traps, and the interface state density cannot be sufficiently reduced, thereby reducing the effect of nitriding passivation;

[0010] 4) NH 3 Passivation also introduces excess N atoms throughout the dielectric, resulting in SiO 2 The breakdown electric field strength of the dielectric is significantly reduced, reducing the SiO 2 Gate Dielectric Reliability

Images