| Traditional atom probe applys a positive electric field on metal sample surface to produce positive ions by field evaporation method, and analyses these ions through measuring its flight time. Because traditional atom probe used to obtain positive ion with very strong electric field that is so strong as to each a few electron volts each nm, it can make chemical state of sample surface particle change. So atom probe can measure sample surface chemical composition, but is obviously difficult to reflect the true chemical state of surface particle. In order to reflect the chemical state of sample surface more truly, the subject of field emission negative ion as the complementary of positive ion probe technique has been put forward and tried hard to develop. The acquisition of field emission negative ion and its time-of-flight Spectra (TOPS) brings up to negative ion atom probe invention. This thesis research works aims at the method and the mechanism of production negative ion by field emission.It is important to study on negative ion which is in a metastable state combined alom or molecule with electron. Negative ion has a strong chemical extreme activation. In this thesis, a kind of negative ion is produced on specimen surface utilizing field emission technology and its TOPS is reported. The relation between the sample surface state, the change of volts on the specimen and negative ion production is presented. According to experiment results, explanation of negative ion production mechanism with this method has put forward. Thinking of the chemical absorption of special site is an essential step and the inducing of quickly change electric field is a key step in the process of negative ion production. Discovering the mechanism of production negative ion by field emission lets people to get a new method of negative production and develops a new surface analysis technology. Moreover, it could help us to get more details of the mid-process in the chemical reaction on surface.
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