At present

field emitting cold cathode materials

including molybdenum

silicon

diamond carbon films

diamond-like carbon films and carbon nanotubes

are being developed. With each of these materials having their own shortages

it is important to seek some new field emitting cold cathode materials. Lanthanum hexaboride (LaB

6

) is a material with low work function

low resistivity

low sputtering yield

high melting point and high chemical stability. It has been widely used as thermionic emitters. On the other hand

LaB

6

is also an excellent material for use as field emission cathodes. Some field emitting cold cathode single tips in-cluding LaB

6

molybdenum

tungsten and tungsten rhenium were fabricated by using electro-chemical etching method. The electron emission characteristics of these cold cathodes were studied in a diode test cell in vacuum system. Changing the anode voltage at a pressure of 1×10-3 Pa

the current density of single crystal LaB

6

was compared with other material cathodes. It showed that LaB

6

was one kind of excellent materials to act as field emitting cold cathode

whose current density was much higher than any other materials. In addition

LaB

6

field emission arrays were attempted to be fabricated by using electro-chemical etching method. The a-type si-licon layer was depositing by PECVD as mask. Electrolytes in this process were ethanol (CH

3

CH

2

OH) containing 2% hydrochloric acid (HCl) and the electrolytic current was 0.6 mA. The SEM showed that the substrate and surface of single crystal LaB

6

tips were both smooth. The height of LaB

6

tips was about 1.7μm. The uniformity of the tips was fine

while due to the erosion selectivity for different crystalloid surface in electro-chemical etching method

serious anisotropic phenomenon was observed for LaB

6

tips. It demonstrated that

seeking some new electrolytes or using other special dry etching methods instead of wet etching methods

maybe effective to fabricate excellent LaB

6

field emitting cold cathode tips. These experimental conclusions were constructive to direct the application of LaB

6

to field emission cathodes further.