This work comprehensively analyses the device physics of a charged plasma-doped InGaAs_5.86GaAs_5.65 Tunnel field effect transistor (TFET) biosensor featuring a dual metal gate configuration. The device is simulated using Silvaco Atlas TCAD, with HfO₂ employed as the gate dielectric alongside a nanocavity to enhance biosensing performance. The investigation focuses on crucial device parameters, including energy band profiles, potential distribution, electric field variations in both lateral and vertical directions, and electron concentration dynamics. Outcomes indicate that the biosensor keeps a superior response in the ambipolar region, with a drain current (I_D) or an on current (I_ON) of ~10^-4, due to the amalgam of the dual metal gate and InGaAs/GaAs heterostructure. This configuration also assists in supervising the flow of the carriers and, therefore, improves biosensing sensitivity and specificity. The results emphasize the advantage of this TFET configuration for next-generation biosensing technologies.