III-Nitride P-Contact with Transparent Insulating Layer

The patent employs a composite contact structure consisting of multiple layers including a transparent conductive oxide layer (such as ITO or ZnO), a reflective metal layer (such as Ag or Al), and intermediate barrier/adhesion layers (such as Ti, Cr, or Ni). This composite structure combines the high transparency and conductivity of oxides with the high reflectivity of metals, while intermediate layers provide adhesion and prevent diffusion, thereby achieving both high light extraction efficiency and low optical absorption simultaneously

The patent introduces intermediary layers between the transparent conductive oxide and the reflective metal, as well as between the metal and the III-nitride semiconductor layer. These intermediary layers (such as Ti, Cr, Ni, or their oxides) serve as adhesion promoters and diffusion barriers, enabling the reflective metal to function effectively without directly contacting the semiconductor, thus preventing both adhesion failure and excessive optical absorption

The patent creates a composite contact system where Ag (or other reflective metals) is combined with transparent conductive oxides and intermediate metal/oxide layers. The TCO layer provides low contact resistivity and chemical stability with III-nitride, while the intermediate layers provide mechanical adhesion. This composite approach maintains the electrical and optical benefits of Ag while eliminating its adhesion and electro-migration problems

The patent introduces intermediary barrier and adhesion layers (such as Ti, Cr, Ni, or their oxides) between the Ag reflective layer and the III-nitride semiconductor. These intermediaries prevent direct contact between Ag and the semiconductor, blocking diffusion paths that would otherwise lead to adhesion failure and electro-migration. The intermediaries maintain electrical conductivity while providing structural stability

The patent segments the contact function into distinct layers, each optimized for a specific function: the TCO layer handles electrical conductivity and optical transparency, the intermediate layers handle adhesion and diffusion prevention, and the reflective metal layer handles light reflection. This segmentation allows each layer to be independently optimized and manufactured using standard semiconductor processes, making the complex structure manufacturable

The patent designs the multi-layer contact structure to perform multiple functions simultaneously: electrical conduction, optical reflection, mechanical adhesion, and diffusion prevention. By integrating these functions into a single contact structure that can be deposited in one manufacturing sequence, the patent achieves high performance without proportionally increasing manufacturing complexity