Can't get rid of vertical margin in Widget - flutter

Question

I've got an issue with the button on the right... The round green one has some kind of vertical margin (in yellow) and I don't know how to get rid of it and its making me crazy !
I would like it to be like the RaisedButton on the left.
This is the code that creates this :
Widget myWidget() {
return Row (
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
Container(
color: Colors.red,
child:
RaisedButton(
color: Colors.red,
onPressed: () {},
child: Container(child: Text("+")),
)),
Container(
color: Colors.yellow,
child:ClipOval(
child: Container(
child:InkWell(
onTap: () {
setState((){
});
},
child: myButton("+")
)
)
),
),
And the myButton widget :
Widget myButton(text) {
return new Container(
margin: EdgeInsets.only(left: 20.0, right: 20.0, top: 0, bottom: 0), //horizontal margin works but vertical margin is not impacted by whatever I put here
padding: EdgeInsets.all(20),
decoration: new BoxDecoration(
shape: BoxShape.circle,
color: Colors.green,
),
child: new Text(text,
style: new TextStyle(
color: Colors.white,
fontSize:
50.0)),
);
}
The parent widget :
return Column(
mainAxisAlignment: MainAxisAlignment.spaceAround,
children: [
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
mainAxisSize: MainAxisSize.max,
children: [
Align(...),
Align(...)
]
),
Expanded(
child: Card(
child: InputControlParent(),
),
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
myWidget() #<= child presented above
],
)
],
);

Answer 1

Parent code.
Widget myWidget() {
return Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Container(
color: Colors.red,
child: RaisedButton(
color: Colors.red,
onPressed: () {},
child: Container(child: Text("+")),
)),
Container(
height: 100,//i put height
width: 100,// i put weidth
color: Colors.yellow,
child: InkWell(
onTap: () {
setState(() {});
},
child: myButton("+")),
),
])
myButton widget :
Widget myButton(text) {//remove the margin that not needed
return new Container(
padding: EdgeInsets.all(20),
decoration: new BoxDecoration(
borderRadius: BorderRadius.circular(50),
color: Colors.green,
),
child: Center(
child: new Text(text,
style: new TextStyle(color: Colors.white, fontSize: 50.0)),
),
);
}