Do you set your alarm on your smartphone before going to bed? Personally I have no problem with that. This particular blog post lists some reasons why you shouldn’t use your smartphone as an alarm and instead, go for a conventional clock. The problems listed in this blog post may not be applicable to everybody (they don’t apply to me) but if some of them apply to you, maybe you should consider either changing your smartphone-using pattern, or actually go for a conventional clock.
The only problem with the conventional clock is that the snooze feature is missing (or is it available in some clocks?). If you aren’t aware of the snooze feature, it allows you to sleep a few minutes extra if you tap “Snooze” on your screen when the alarm sets off in the morning. I find this feature quite useful. What happens is, I normally set my alarm to go off at 4:45 AM in the morning because I want to get up at around 5 AM. Since I want to catch another quick nap before I finally get up, I hit snooze button, the alarm stops and then it again starts ringing after 10 minutes.
I don’t have any problems using my phone because I can easily control the impulse to check messages and do other stuff when I’m lying in my bed. For instance, before even coming to my bedroom I set my alarm asking Google Now to set it up for me. I don’t even look at my phone screen when I come to my bedroom. It is not recommended that you put your phone near your head when you are sleeping so I put it slightly away. I had this tendency to check Twitter updates but when I realised that it was more of a disturbance than a convenience, I stopped using Twitter from my mobile phone. So I can keep using my smartphone as alarm without any problem.
But if you cannot resist looking at your phone again and again while you are in your bed, the best would be to switch to the conventional alarm clock.