Modelling/simulation and high-frequency characterization of hetero-junction Avalanche Transit Time (ATT) oscillators, operating in tuned harmonic mode, are reported in the paper. An equivalent circuit, that incorporates self-consistent, non-linear, single-frequency impedance and admittance properties of the device at fundamental, 1st harmonic and 2nd harmonic mode of oscillation frequencies within the THz (0.5–1.5 THz) domain, is simulated. The prospects of Si/4H-SiC versus Si/6H-SiC exotic hetero structures are studied and compared for the generation of considerable amount of RF-power at higher harmonic THz region. For this, a generalised non-linear Mixed Quantum Drift Diffusion (MQDD) model is developed indigenously. The authors have made the simulator realistic by incorporating the temperature dependent carrier ionization rate, saturation drift velocity, mobility and effective mass of the base material-pairs in the analysis. In addition to these, the effects of punch-through phenomena as well as parasitic series resistance related detrimental issues are duly addressed in the present analysis. The authors have made the model realistic by studying the performance of the proposed novel structures under room temperature as well as under elevated temperature conditions. Due to the incorporation of hetero-structure in the active region of the device, considerable amount of power could be generated at 2nd harmonic oscillation frequency (~ 1.7 THz). The study shows that both the Si/4H-SiC and Si/6H-SiC hetero-junction devices are oscillating at 0.5 THz (fundamental frequency). Si/4H-SiC hetero-junction device, due to its less lattice mismatch factor, is more efficient (45%) than its Si/6H-SiC (15%) counterpart under similar structural/electrical/thermal operating conditions. The validity of the MQDD model is established in this paper by comparing the data with corresponding experimental observations at microwave/millimeter-wave region. To the best of authors’ knowledge, this is the first report on harmonic power generation from Si/4H-SiC and Si/6H-SiC hetero-junction ATT devices at higher terahertz region.

本文报道了在调谐谐波模式下工作的异质结雪崩渡越时间（ATT）振荡器的建模/仿真和高频特性。模拟了等效电路，该电路在THz（0.5–1.5 THz）域内的振荡频率的基波，一阶谐波和二阶谐波模式下结合了设备的自洽，非线性，单频阻抗和导纳特性。研究并比较了Si / 4H-SiC与Si / 6H-SiC异质结构的前景，并在高谐波THz区域产生了大量的RF功率。为此，本地开发了一种广义的非线性混合量子漂移扩散（MQDD）模型。作者通过结合温度相关的载流子电离速率，使模拟器变得现实，分析中基础材料对的饱和漂移速度，迁移率和有效质量。除了这些之外，在本分析中适当解决了击穿现象以及与寄生串联电阻相关的有害问题的影响。通过研究建议的新型结构在室温以及高温条件下的性能，作者使模型变得现实。由于在器件的有源区中引入了异质结构，因此在二次谐波振荡频率（约1.7 THz）下会产生大量的功率。研究表明，Si / 4H-SiC和Si / 6H-SiC异质结器件均以0.5 THz（基本频率）振荡。Si / 4H-SiC异质结器件，由于其晶格失配因子较小，在类似的结构/电气/热运行条件下，其效率比其Si / 6H-SiC（15％）更高（45％）。通过将数据与微波/毫米波区域的相应实验观测值进行比较，建立了MQDD模型的有效性。据作者所知，这是关于在较高太赫兹区域Si / 4H-SiC和Si / 6H-SiC异质结ATT器件产生谐波功率的第一份报告。