Electron field emission characteristics of textured silicon surface

A textured silicon surface was prepared by chemical etching. The textured s urface was covered with small silicon tips. The base diameter of the tips i s random and the size is from less than 1-10 mum. A held emission emitter t hat shows a lower turn-on voltage has been fabricated by using aqueous pota ssium-hydroxide solutions with isopropyl alcohol added as a complexing agen t. The silicon wafers were (100) monocrystalline n-type with a resistivity of 0.01 Omega cm. A texturing process using dilute inorganic alkaline in is opropyl alcohol solution is investigated. This causes the formation of rand omly distributed pyramids on the (100) cyrstallographic plane without any m asking pattern. Dilute alkaline solutions show a low-etching rate of typica lly 0.5 mum/min. The anisotropy arises from hydrogen bubbles which are able to stay on the silicon surface for a shea time during etching. The diamete r of the bubbles, their density, and the rate of the etching reaction defin e the geometry of the textured silicon surface. The silicon tip size and th e density is affected by: the concentration of isopropyl alcohol, potassium hydroxide, pretreatment of silicon substrate, and the temperature of the e tchant. The turn-on voltage of the textured silicon surface was approximate ly at 25 V/mum when the emission current density reaches 1 muA/cm(2). This compared with the turn-on field about 35 V/mum on a silicon tip array fabri cated by using an isotropic etching solution of nitric acid. A silicon carb ide layer was formed on the textured silicon surface by using metal vapor v acuum are ion implantation. The turn-on voltage can be lowered to approxima tely 9 V/mum when the emission current density reaches 1 muA/cm(2). (C) 200 1 American Vacuum Society.