掩蔽層 的英文怎麼說
中文拼音 [yǎnbìcéng]
掩蔽層
英文
masking layer- 掩 : 動詞1 （遮蓋; 掩蔽） cover; hide 2 （關; 合） shut; close 3 [方言] （被卡住） get squeezed [pinch...
- 蔽 : Ⅰ動詞（遮擋; 遮蔽; 蒙蔽） cover; block; hide; shelter; spread over Ⅱ名詞（姓氏） a surname
- 層 : i 量詞1 （用於重疊、積累的東西 如樓層、階層、地層） storey; tier; stratum 2 （用於可以分項分步的...
- 掩蔽 : screen; shelter; cover; mask; blanket; hide; defilade; audio masking; aural masking; ensconce
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At the initial stage of planar technique, b was employed as ideal diffusion impurity in base - region of npn si planar devices because of the match of its solid - solubility and diffusion coefficient in si with those of p in emission - region, and the good shield effect of sio2 film to b. but because of the relatively large solubility ( 5 1020 / cm3 at 1000 ) and the small diffusion coefficient, the linear slowly - changed distribution of acceptor b in pn junction can not be formed, which could not cater to the requirement of high - reversal - voltage devics. thereafter b - a1 paste - layer diffusion technology and close - tube ga - diffusion technology had been developed, while the former can lead to relatively large the base - region deviation and abruptly varied region in si, which caused severe decentralization of current amplification parameter, bad thermal stability and high tr ; the latter needed the relatively difficult pack technique, with poor repeatability, high rejection ratio, and poor diffusion quality and productio n efficiency
在平面工藝初期，由於b在硅中的固溶度、擴散系數與n型發射區的磷相匹配， sio _ 2對其又有良好的掩蔽作用，早被選為npn硅平面器件的理想基區擴散源，但b在硅中的固溶度大（ 1000時達到5 10 ~ （ 20 ） ，擴散系數小， b在硅中的雜質分佈不易形成pn結中雜質的線性緩變分佈，導致器件不能滿足高反壓的要求，隨之又出現了硼鋁塗層擴散工藝和閉管擴鎵工藝，前者會引起較大的基區偏差，雜質在硅內存在突變區域，導致放大系數分散嚴重，下降時間t _ f值較高，熱穩定性差；後者需要難度較大的真空封管技術，工藝重復性差，報廢率高，在擴散質量、生產效率諸方面均不能令人滿意。
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