材料科學(xué)與工程 材料物理與化學(xué)，外文文獻(xiàn)翻譯及原文

Properties of Silicon Doped with Iron or Copper

鐵或銅摻雜的硅特性

Iron introduces a donor level into silicon at 0.40 ev from theva lence band observed both in crystals doped in the melt and incrystals into which iron was diffused at 1200'C. This level convertsanomalously to a level 0.55 ev from the conduction band onstanding at room temperature. The conversion is reversible inthe range~70'—200'C; above 200'C, the electrical activity ofiron irreversibly disappears. No evidence for acceptor action ofiron was found. The electrically active solubility of iron, 1.5&&10"cm'at 1200'C, is higher than the radiotracer solubility but theformer was measured in more rapidly quenched samples. Thedistribution coeS.cient is 8)(10 . Preferentialtrapping ofelectrons by iron centers was shown by Hall mobility measure-ments on optically-excited charge carriers. Lifetime studies bythe photoconductive decay method indicated a larger capturecross section for electrons than for holes.Copper introduced a donor level at 0.24 ev and an acceptorlevel at 0.49 ev, both as measured from the valence band. Themaximum electrical activity in quenched samples was 5X10'4cm'out of a total concentration of10"cm'at 1200'C. Infraredphotoconductivity spectra support the position of the deep levelsdue to iron and copper.The apparent lack of electrical activity or inconsistency inproducing a level is discussed for a number of other elements insilicon. Precipitation while cooling from high temperature isbelieved to reduce the soluble component of most of these ele-ments below the observable limit of~10'4cm'.

1200攝氏度0.40電子伏下從價(jià)帶中觀察不管是在熔體中的晶體摻雜還是鐵擴(kuò)散，都能發(fā)現(xiàn)硅中的鐵引入了深能級(jí)。這個(gè)能級(jí)的轉(zhuǎn)換異于在室溫下0.55電子伏下導(dǎo)帶的能級(jí)。在70攝氏度到200攝氏度是可逆的；超過200攝氏度，鐵的電活性便完全的消失了。沒有證據(jù)表明鐵的受體作用被發(fā)現(xiàn)。鐵的電活性溶解度，在1200攝氏度是1.5×1016，，它比放射性示蹤劑的溶解度要高，但是前者是在更迅速淬火的樣品中測試出來的。分配系數(shù)是8×10-6。優(yōu)惠的鐵中心的電子俘獲能通過光激發(fā)載流子的霍爾遷移率的測量顯示出來。少子壽命可以通過光電導(dǎo)衰減法來顯示一個(gè)更大的俘獲截面的電子比空穴。
銅在0.24電子伏能引進(jìn)一個(gè)深能級(jí)和一個(gè)0.49電子伏下的受主能級(jí)，都作為測量的從價(jià)帶。對(duì)打的點(diǎn)活動(dòng)在淬火樣品為5×1014㎝的1200攝氏度。紅外光電導(dǎo)譜支持定位鐵和銅的深能級(jí)的位置。電活動(dòng)生產(chǎn)水平明顯缺乏或不一致的討論可以與其他硅中的元素一起。從高溫冷卻后的沉淀被認(rèn)為可以去掉大部分低于可溶性成分觀察限制~1014㎝-3的解釋。