Kev faib tawm ntawm silicon hlau

Kev faib tawm ntawm silicon hlau feem ntau yog cais los ntawm cov ntsiab lus ntawm peb lub ntsiab impurities ntawm hlau, txhuas thiab calcium uas muaj nyob rau hauv silicon hlau muaj pes tsawg leeg. Raws li cov ntsiab lus ntawm hlau, txhuas thiab calcium hauv hlau silicon, hlau silicon tuaj yeem muab faib ua 553, 441, 411, 421, 3303, 3305, 2202, 2502, 1501, 1101 thiab lwm qib sib txawv.

Hauv kev lag luam, nws yog xim hlau silicon feem ntau yog tsim los ntawm carbon txo cov silicon dioxide nyob rau hauv hluav taws xob furnaces. Kev sib npaug tshuaj lom neeg: SiO2 + 2C → Si + 2CO Lub purity ntawm silicon ua li no yog 97 ~ 98%, uas yog hu ua hlau silicon. Tom qab ntawd nws yog yaj thiab recrystallized, thiab impurities raug tshem tawm nrog cov kua qaub kom tau nws cov hlau silicon nrog purity ntawm 99.7 ~ 99.8%.

Silicon hlau feem ntau yog tsim los ntawm silicon, yog li nws muaj cov khoom zoo sib xws rau silicon. Silicon muaj ob allotropes: amorphous silicon thiab crystalline silicon. Amorphous silicon yog cov hmoov grey-dub thiab yog ib qho microcrystal. Crystalline silicon muaj cov qauv siv lead ua thiab cov khoom semiconductor ntawm pob zeb diamond, melting point 1410 ℃, boiling point 2355 ℃, Mohs hardness 7, brittle. Amorphous silicification yog nquag thiab tuaj yeem hlawv hnyav hauv oxygen. Nws reacts nrog cov hlau tsis muaj hlau xws li halogens, nitrogen thiab carbon ntawm qhov kub thiab txias, thiab tuaj yeem cuam tshuam nrog cov hlau xws li magnesium, calcium thiab hlau los tsim cov silicides. Amorphous silicon yuav luag insoluble nyob rau hauv tag nrho cov inorganic thiab organic acids, nrog rau hydrofluoric acid, tab sis soluble nyob rau hauv sib xyaw acids ntawm nitric acid thiab hydrofluoric acid. Concentrated sodium hydroxide tov tuaj yeem yaj amorphous silicon thiab tso tawm hydrogen. Crystalline silicon yog qhov tsis muaj zog, txawm tias nyob rau hauv qhov kub siab tsis ua ke nrog oxygen, nws tsis soluble nyob rau hauv ib qho inorganic thiab organic acids, tab sis soluble nyob rau hauv nitric acid thiab hydrofluoric acid tov acid thiab concentrated sodium hydroxide tov.