Modulation-Acceptor Doping of SiO2 as Novel Doping Method for Silicon Nanowires (MADSiNano)

SiO2 的调制受主掺杂作为硅纳米线的新型掺杂方法 (MADSiNano)

• 批准号: 456993281
• 负责人: Professor Dr. Daniel Hiller
• 金额: --
• 依托单位: Abteilung 7 - Temperatur und Synchrotronstrahlung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/456993281?language=en
• 关键词: Modulation; Acceptor; Doping; SiO2; Novel

Silicon (Si) nanowires with few nanometers in diameter play a key role in the further development of the microelectronic transistor technology, which is essential for virtually all electronic devices. Nanowires enable maximum gate control over the source-drain current via the gate-all-around field effect transistor (GAA-FET) architecture. For the electronic functionalization of nanowire transistors several concepts are available (p/n-junctions, tunnel-FETs, junctionless transistors). However, all them rely on the conductivity control by classical impurity doping (using e.g. phosphorus or boron). On the nanoscale, reliable and efficient doping is impeded by a multitude of physical and technological problems. These problems include e.g. the undesired diffusion of dopants, segregation or deactivation of dopants at interfaces, dielectric and quantum confinement that inhibit the ionization of an impurity as well as statistical problems when attempting to dope ultrasmall Si nanovolumes with an identical amount of a defined number of dopant atoms.In this project we want to pursue a theoretical concept to adopt modulation doping known from III-V semiconductors for Si. Modulation doping means that the parent dopant atoms are spatially separated from the volume that is to be doped by embedding them into an adjacent material with a higher bandgap. Density functional theory (DFT) calculations predicted that aluminum (Al) atoms in SiO2 have an unoccupied state below the Si valence band edge, which upon electron capture creates a hole in the Si as majority charge carrier. Thereby, the SiO2 embedding a Si nanostructure is doped, whereas the free majority charge carriers contribute to the conductivity of the Si. All the problems associated to direct Si doping are circumvented in that way. In extensive preliminary work we proved the existence of this Al-induced acceptor state and determined several fundamental properties. Now, we want to adopt this concept to Si nanowires to demonstrate a massive increase of the conductivity via modulation acceptor doping of the SiO2 shell and to fabricate and characterize functional nanowire transistor test devices. In addition to Al, DFT calculations suggest 4 other possible elements, which might represent SiO2 modulation acceptors for Si. In the project, these elements will be investigated in detail and processes will be developed to implement them into Si nanowire transistors to enable a comparison of the doping properties of the different modulation acceptor elements.

直径几纳米的硅（Si）纳米线在微电子晶体管技术的进一步发展中起着关键作用，几乎是所有电子器件所必需的。纳米线通过栅极全能场效应晶体管（GAA-FET）结构实现对源极漏极电流的最大栅极控制。对于纳米线晶体管的电子功能化，有几个概念可用（p/n结，隧道场效应管，无结晶体管）。然而，它们都依赖于传统的杂质掺杂（如磷或硼）来控制电导率。在纳米尺度上，可靠和有效的掺杂受到许多物理和技术问题的阻碍。这些问题包括掺杂剂的扩散、界面处掺杂剂的偏析或失活、抑制杂质电离的介电和量子限制，以及试图用相同数量的确定数量的掺杂剂原子掺杂超小硅纳米体积时的统计问题。在这个项目中，我们想要追求一个理论概念，即采用III-V半导体中已知的调制掺杂来制备Si。调制掺杂是指将母掺杂原子嵌入具有较高带隙的相邻材料中，从而使其在空间上与要掺杂的体积分离。密度泛函理论（DFT）计算预测SiO2中的铝（Al）原子在Si价带边缘以下具有一个空占据态，这在电子捕获后在Si中产生一个空穴作为主要的电荷载流子。因此，嵌入Si纳米结构的SiO2是掺杂的，而自由多数载流子有助于Si的导电性。所有与硅直接掺杂有关的问题都是通过这种方式解决的。在广泛的初步工作中，我们证明了这种铝诱导受体状态的存在，并确定了几个基本性质。现在，我们希望将这一概念应用于硅纳米线，通过在SiO2外壳中掺杂调制受体来证明电导率的大幅提高，并制造和表征功能性纳米线晶体管测试设备。除了Al之外，DFT计算还提出了另外4种可能的元素，它们可能代表SiO2对Si的调制受体。在该项目中，将对这些元件进行详细研究，并开发将其实现到硅纳米线晶体管中的工艺，以比较不同调制受体元件的掺杂特性。