美国BDH化学公司最近研制成一种性能优越的新GaAs外延片,用它制成的调正变容二极管,其微波调谐系数的最大值将增加一倍多。为满足所必需的电容变化,该GaAs外延片在活性区域的掺杂浓度分布,是由该公司通过特殊工艺制备而得,他们使其从衬底表面到外延层表面的载流子浓度分布逐渐降 BDH Chemical Company recently developed a new GaAs epitaxial wafers with superior performance. With its positive-working varactor diodes, its maximum microwave tuning factor will more than double. To meet the necessary capacitance changes, the GaAs epitaxial wafers in the active region of the doping concentration distribution is prepared by the company through a special process, they make it from the substrate surface to the surface of the epitaxial layer carrier concentration gradually drop