摘要
采用定位横断面制样的高分辨电子显微技术（ＨＲＥＭ）观察了Ｐ＋ －Ｓｉ０．６５Ｇｅ０．３５／Ｐ－Ｓｉ异质结内光发射红外探测器的微结构．该器件光敏区是由３ 层Ｐ＋ －Ｓｉ０．６５Ｇｅ０．３５和２ 层ＵＤ－Ｓｉ（未掺杂硅）组成，Ｓｉ０．６５Ｇｅ０．３５／ＵＤ－Ｓｉ层间界面不明锐，有一个由于Ｇｅ 原子不均匀扩散造成的过渡带．这个过渡带缓和了界面的失配应力，因而未观察到界面晶体缺陷和严重的晶格畸变．在光敏区边缘有呈倒三角形的缺陷区，缺陷的主要类型为层错和微孪晶．层错在（１ １１）面上，而微孪晶的厚度约为２～４晶面间距，其孪晶面为（１ １１）．非晶ＳｉＯ２ 台阶上的Ｓｉ０．６５Ｇｅ０．３５和ＵＤ－Ｓｉ层由随机形核生长的多晶组成。
Microstructure of P\++\|Si\-\{0.65\}Ge\-\{0.35\}/P\|Si heterojunction internal photoemission (HIP) infrared detector with a stacked structure has been observed by using localization cross\|section high resolution electron microscopy.The photo\|sensitive region in the detector consists of 3 P\++\|Si\-\{0.65\}Ge\-\{0.35\} layers and 2 undoped Si(UD\|Si) layers. The interface between Si\-\{0.65\}Ge\-\{0.35\} and UD\|Si is not sharp and has a transition area due to nonuniform diffusion of Ge atoms.The misfit stress on the interface is distributed gradiently in normal direction of it.Therefore the crystal defects and serious lattice deformations on the interface have not been observed.A defect area in the shape of inverted triangle exists in the edges of photo\|sensitive region.The main types of the defects in the area are stacking faults and microtwins.The stacking faults are on (1 11),and the thickness of the microtwins is about 2~4 lattice distance and the twin plane is (1 11).The Si\-\{0.65\}Ge\-\{0.35\} and UD\|Si layers on amorphous SiO\-2 step consist of polycrystals grown due to random nucleation,and are in the shape of waves.
基金
国家自然科学基金
