A High Mobility Electron Transistor, HEMT, (10) and a capacitor (14, 18, 20, 22, 24) co-formed on an integrated circuit share at least one structural feature, thereby tightly integrating the two components. In one embodiment, the shared feature may be a 2DEG channel of the HEMT (10), which also functions in lieu of a base metal layer of a conventional capacitor (12). In another embodiment, a dialectic layer of the capacitor (14, 18, 20, 22, 24) may be formed in a passivation step of forming the HEMT (10). In another embodiment, a metal contact of the HEMT (10) (e.g., source, gate, or drain contact) comprises a metal layer or contact of the capacitor (22). In these embodiments, one or more processing steps required to form a conventional capacitor (12) are obviated by exploiting one or more processing steps already performed in fabrication of the HEMT (10).