# Investigation of Hydrogen Flux Influence on InGaP Layer and Device Uniformity
###### Abstract  
In this study, we conduct a comprehensive examination of the influence of hydrogen (H\({}_{2}\)) carrier gas flux on the uniformity of epitaxial layers, specifically focusing on the InGaP single layer and the full structure of the InGaP/GaAs heterojunction bipolar transistor (HBT). The results show that an elevated flux of H\({}_{2}\) carrier gas markedly facilitates the stabilization of layer uniformity. Optimal uniformity in epitaxial wafers is achievable at a suitable carrier gas flux. Furthermore, this study reveals a significant correlation between the uniformity of the InGaP single layer and the overall uniformity of HBT structures, indicating a consequential interdependence. InGaP; H\({}_{2}\) flux; HBT; uniformity check for updates  
[19]http://www. different fabrication conditions. Coupled with high yields and a manufacturing process, these attributes facilitate large-scale production and applications, positioning InGaP/GaAs heterojunctions as a formidable choice in advanced semiconductor technologies [16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26]. The integration of large-size epitaxial wafers into semiconductor manufacturing significantly enhances production efficiency and material usage, thereby reducing the cost per unit area. In the fundamental current industrial landscape, which emphasizes high efficiency and cost-effectiveness, the adoption of large-size wafers is crucial. They not only streamline production but also minimize material waste across various processing stages, leading to substantial cost savings. Yet, the shift towards larger wafers introduces complexities in maintaining epitaxial uniformity. The expansion of wafer size complicates control over temperature gradients, gas flux, and reaction rates during epitaxy, potentially resulting in uneven thickness, composition, and crystal structure across the wafer. This variability can compromise product stability. To address these challenges, the development of advanced epitaxial techniques that ensure consistent high-quality growth on large wafers is a key focus in semiconductor research, underscoring its significance for future manufacturing innovations [27; 28]. The study of large-sized InGaP and In\({}_{0.49}\)Ga\({}_{0.51}\)P/GaAs heterojunction bipolar transistor (HBT) epitaxial processes is therefore of fundamental importance. During the epitaxial growth of InGaP, achieving high-quality layers demands precise control over the experimental conditions, notably within a temperature range governed by mass transport. This specific range is favored because it minimizes external influences on the growth process. Here, the kinetics of epitaxial growth rely on the diffusion rate of reactants to the surface, making the growth rate independent of temperature fluctuations. This independence is crucial as it grants researchers the ability to finely adjust the process, specifically through the modulation of the flux and concentration of group III sources. Such adjustments enable the precise tuning of the growth rate, optimizing the epitaxial layer's thickness, composition, and crystal structure, thereby enhancing the material's overall quality. Furthermore, within this same temperature bracket, the growth rate can be effectively estimated through a straightforward boundary layer model, encapsulated by the following equation:  
\[\mathrm{r_{g}}=\mathrm{C_{0}P_{TMGa}(v/P)}^{1/2}\]  
Here, \(\mathrm{C_{0}}\) represents a constant and \(\mathrm{P_{TMGa}}\) denotes the absolute partial pressure of TMGa, which is entirely depleted at the interface in the gas input stream. Additionally, \(\mathrm{v}\) symbolizes the gas flux, while \(\mathrm{P}\) refers to the system's overall pressure. The aforementioned equations demonstrate that, at a constant growth pressure, the gas flux markedly affects the growth rate, which in turn critically influences the uniformity of the epitaxial wafer [29; 30; 31]. This study is governed by the gas flux, which is modulated by the total hydrogen (H\({}_{2}\)) carrier gas flux.