Mechanisms for forming sourcedrain regions of field effect transistors are provided. The delays are determined by calculating a delay value metric for each input pin and output pin and by assigning a delay value metric to the respective pin. The server checks the identity and creditworthiness of the grantor, and then establishes a trust account. The multimedia content may further include customizable templates in which business messages may be generated. The lighting device for the ventilating fan further comprises hooks formed on the radiator and a second positioning lug formed on the power pack module, wherein the hooks and the second positioning lug are used for fixing the lighting device on the ventilating fan.