All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Not performing the morning prayer on time without deliberation or laziness on your part does not turn you into a disbeliever at all. Furthermore, if you have utilized the necessary means of waking up for prayer without negligence, then you are not even sinful for not performing the prayer at its specified time as the pen (of registering the deeds) is lifted for the sleeping person (i.e. he is not held accountable) as stated by the Prophet, sallallaahu ‘alayhi wa sallam.
We instruct you to seek the help of Allaah The Exalted. Ask Him for success and follow the guidance of the Prophet, sallallaahu ‘alayhi wa sallam, in disliking staying up late after Al-‘Ishaa’ prayer. It is narrated in Saheeh Al-Bukhari on the authority of Abu Barzah that the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, disliked sleeping before ‘Ishaa’ and chatting after it.
Other means that may help you perform Fajr prayer on time is to ask someone to wake you up by phone or by knocking on your door or the like.
Allaah Knows best.