Oxide semiconductor film transistor trap state density extraction method

Abstract

The invention relates to an oxide semiconductor film transistor trap state density extraction method, belongs to the technical field of a semiconductor device and includes semiconductor and gate insulation layer interface trap state extraction and internal trap state extraction of a semiconductor. The method comprises steps that (1), forward bias stresses with different durations are applied to an oxide semiconductor film transistor, and a corresponding transfer characteristic curve is tested; 2), based on transfer characteristic change rules, a threshold voltage drift mechanism is analyzed, and the change relation of the threshold voltage drift along with the time is determined; 3), if the threshold voltage drift and the applied stress time satisfy an expansion index model, characteristic temperature of an internal trap state of the semiconductor is extracted; and 4), the relationship between sub threshold amplitude and the trap state is utilized, semiconductor and gate insulation layer interface state density and internal trap state density of the semiconductor are extracted. The method is advantaged in that the film transistor interface trap state and the internal trap state can be simultaneously extracted, the calculation process is simpler compared with methods in the prior art, restriction conditions are a few, and the application scope is wide.

Description

technical field [0001] The present invention relates to the technical field of semiconductors, and more specifically, to a method for extracting trap state density of an oxide semiconductor thin film transistor. Background technique [0002] Oxide semiconductor thin film transistors have the advantages of high mobility, transparency, compatibility with the low-temperature preparation process of amorphous silicon, flexible display, and good uniformity in large-area production. They have attracted great attention and are widely used in AMLCD and AMOLED. , logic gates for ring oscillators, sensors, etc. [0003] The trap states of thin film transistors include the trap states at the interface between the semiconductor and the gate insulating layer and the trap states in the semiconductor body. Similar to hydrogenated amorphous silicon thin film transistors, oxide semiconductor thin film transistors also have more non-uniformly distributed bandgap defect states. These bandgap s...

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Problems solved by technology

2) Field effect (F-E) method: This method assumes that the conduction mechanism of the transistor is mainly trap state-limited conduction. The existence of this prerequisite makes it difficult to extract the acceptor trap state of the oxide semiconductor thin film transistor.

However, light will change the material properties and change the distribution of trap states

4) Use the Mel-Nedo principle to extract, but the flat-band voltage and the Mel-Nedo factor of the transistor need to be known in advance. In addition, this method can only be used when the device works in the sub-threshold region

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