The best and ideal mantra for deep sleep in Hinduism is dedicated to Mahadev Shiva. The mantra should be chanted 108 times before going to sleep. The person chanting the mantra should keep away all kinds of electronic gadgets etc. The person should lie down and imagine Shiva in meditating posture.
Then the person should chant ‘ॐ नमः शिवाय’ 108 times. Again the person should wake up early in the morning around 4:30 AM. Take bath and do other purification rituals. Then the person should light a lamp in the northeast part of the room using pure cow ghee. The devotee should once again chant ‘ॐ नमः शिवाय’ 108 times.
This should be repeated for seven days continuously and the person will soon have deep sleep.