Tkinter - How can I remove the background borders from ttk.Button?

[TurboC]

by default, the buttons from ttk module, have a one pixel border. how can I delete this border? below an example code:

from tkinter import *
from tkinter import ttk

root = Tk()
root.geometry("400x300")

style=ttk.Style()
style.configure("TButton", padding=0, background="#ffffff") # I colored the background border white to make it visible in the window.. but, I don't want it, I want to delete the border!

MyButton = ttk.Button(root, text="I have a white border.. how can I delet it?")
MyButton.place(x=16, y=16)

root.mainloop()

I don't want to change the border color in order to hide it in the window,I want to delete it.