Selectively doped heterojunction CCD

1.中断MOVPE生长界面的表征MOVPE生长的中断通常用于实现尖锐的掺杂分布以及尖锐的成分分布。使用C-V剖面和DLTS研究了这种生长中断对界面电特性的影响。当中断的界面暴露于空气中时，检测到具有与绝缘体-半导体结构处的界面态密度分布类似的宽能谱的深能级的形成。根据统一的无序诱导能隙态模型，这种深能级的形成归因于界面原子规则性的无序。2. AlGaAs中的DX中心在决定选择性掺杂异质结器件的阈值电压方面起着主导作用。然而，DX中心的起源并没有得到澄清，尽管它们很重要。提出了一个新的DX中心模型，认为DX中心的起源是施主杂质-主体键的反键态。该模型基于DX中心相对于主体杂化轨道能量的排列，表明电子态的成键-反键分裂.异质结界面载流子的产生利用CCD结构测量了选择性掺杂异质结界面电子的产生率。结果表明，产生速率仅由Al/AlGaAs肖特基势垒的反向电流决定。反向电流主要由产生-复合电流组成.选择性掺杂异质结CCD的制造和操作选择性掺杂异质结CCD是使用自对准工艺制造的，以保持电极在亚微米范围内的分离。证实了CCD在167 KHz下的成功运行。

1. Characterization of interrupted MOVPE growth interfaceInterruption of MOVPE growth is usually used to realize sharp doping profiles as well as sharp composition profiles. The effect of such a growth interruption on the electrical characteristics of the interface is investigated using C-V profiling and DLTS. When the interrupted interface is exposed to air, formation of deep levels with broad energy spectrum similar to the interface state density distribution at insulator-semiconductor structure are detected. This deep level formation is attributed to the disordering of interface atom regularity based on the unified disorder induced gap state model.2. DX centers in AlGaAsDX centers in AlGaAs play a dominant role in determining the threshold voltages of selectively doped heterostructure devices. The origin of the DX centers was, however, not clarified in spite of their importance. A new model is proposed for DX centers in which anti-bonding state of donor impurity-host bond is attributed to be the origin of the DX center. This model is based on the lineup of DX centers with respect of hybrid orbital energy of the host, suggesting the bonding-antibonding splitting of the electronic state.3. Generation of carriers at the heterojunction interfaceGeneration rate of interface electrons at selectively doped heterojunction interfaces is measured using CCD structures. It is shown that the generation rate is determined solely by the reverse current of the Al/AlGaAs Schottky barrier. The reverse current is mainly composed of generationrecombination current.4. Fabrication and operation of selectively doped heterojunction CCDsSelectively doped heterojunction CCDs are fabricated using self-aligned process to maintain the separation of electrodes in the submicron range. The successful operation of CCDs at 167 KHz is confirmed.