Improving InP DHBT linearity for subTHz broadband operation

亚毫米波和太赫兹频率范围在无线通信、材料传感、无损检测、生物学和农业以及近表面医学成像中的广泛应用中越来越受到关注。电子系统被广泛认为是广泛采用毫米波和太赫兹应用的关键，提供连续波操作，小尺寸和重量，高鲁棒性和低功耗。对于无线通信，在140 GHz和300 GHz左右的大气窗口中存在大量频谱，并且通过标准化机构可用于商业用途。毫米波和太赫兹频率的线性宽带电路还有许多其他工业相关用途，例如在欧洲拥有庞大工业基础的仪器仪表。因此，这一领域的进步直接有利于国家和欧洲的技术主权。为了利用可用频谱，需要具有足够RF输出功率的无线发射器来克服这些频率处的高损耗。增加的晶体管线性使得能够减少放大器回退，并且因此转化为更高的系统功率效率和/或增加的可用发射功率，并且因此在未来的通信系统中增加传输距离。对THz晶体管线性的更好和更基本的理解对于找到满足300 GHz无线系统要求的技术答案至关重要。磷化铟双异质结双极晶体管（InP DHBT）与其他可用的晶体管技术相比，非常适合RF功率放大器、混频器和其他宽带电路。InP表现出类似于硅的击穿场，而InP中较高的电子速度使得能够实现相对厚的集电极设计，从而实现高击穿电压。然而，基极-集电极异质结和高集电极电流密度阻碍了器件的线性性能。对于未来工作在300 GHz的宽带6 G收发器中的放大和混频功能，需要优化的InP HBT结构，以及用于电路设计的精确物理仿真和紧凑器件建模。本项目的目的不仅在于通过优化基极-集电极结的组成来提高InP DHBT器件的线性度，而且还在于全面分析和理解潜在的物理机制。根据项目中获得的见解，应证明高度线性的InP DHBT，并推导出相应的紧凑模型，使电路设计成为可能。

The sub-mm-wave and THz frequency range is gaining interest for wide ranging applications in wireless communication, material sensing, nondestructive testing, biology and agriculture, as well as near-surface medical imaging. Electronic systems are widely seen as a key to widespread adoption of mm-wave and THz applications, offering cw operation, low size and weight, high robustness, and low power consumption. For wireless communications, a vast amount of spectrum in the atmospheric windows around 140 GHz and 300 GHz exists and is being made available for commercial use through standardization bodies. There are many other industrially relevant uses for linear wideband circuits at mm-wave and THz frequencies, e.g. instrumentation, which have a large industrial base in Europe. Advancement in this area therefore directly benefits the national and European technological sovereignty. To take advantage of the available spectrum, wireless transmitters with sufficient RF output power to overcome the high losses at those frequencies are needed. Increased transistor linearity enables a reduction of amplifier back-off and thus translates into higher system power efficiency and/or increased useable transmitted power and therefore increased transmission distance in future communication systems. A better and more fundamental understanding of THz transistor linearity is paramount to finding technological answers to the requirements of 300 GHz wireless systems. The Indium Phosphide Double-Heterostructure Bipolar Transistor (InP DHBT) is - in comparison to other available transistor technologies - very well suited for RF power amplifiers, mixers and other wideband circuits. InP exhibits a breakdown field similar to silicon, whilst a higher electron velocity in InP enables a relatively thick collector design and thus high breakdown voltage. However, the base-collector heterojunction and high collector current densities impede the linearity performance of the devices. For amplification and mixing functions in future wideband 6G transceivers operating at 300 GHz, optimized InP HBT structures are needed, in conjunction with accurate physical simulation and compact device modeling for circuit design. This project aims to not only improve the linearity of InP DHBT devices through optimization of the composition of the base-collector junction, but also at comprehensive analysis and understanding of the underlying physical mechanisms. Based on the insights gained within the project, highly linear InP DHBTs shall be demonstrated and the respective compact model enabling circuit desing shall be derived.