I found a document called The TOGAF Standard, Version 9.2 that describes the Technology Architecture phase in the Architecture Development Method (ADM). This phase focuses on developing a Technology Architecture for an architecture project. The document provides a detailed description of the objectives, inputs, steps, and outputs of this phase. It also includes a diagram illustrating the Phase D: Technology Architecture.
Another architecture design methodology for information technology is ADMIT (Architecture Design Methodology for Information Technology). It is a decision-making tool that helps develop a robust architecture using design forces, strategies, and lifecycle processes.
If you are looking for information on Enterprise Architecture, you might find the Service and Digital Target Enterprise Architecture White Paper useful.