How to brake the player?

I'm making a 3D adventure game, and of course I'm searching A LOT just to make shure I'm doing it everything allright, but sometimes I can't find an answer for my threats with Unity. I'm doing everything as it should be, look:

 private AnimationController animCtrl;
 private SwitchSystem switchSys;
 private Rigidbody rbody;
 private CanWalk canWalk;

 [SerializeField]private float speed = 5000f;
 [SerializeField]private float angularSpeed;

 [SerializeField]private float speedMultiplier;
 [SerializeField]private float speedDivisor;

 [SerializeField]private KeyCode runButton;
 [SerializeField]private KeyCode crowtchButton;

 private float inputV;
 public bool invertVertical;

 [SerializeField]private Transform camTransform;

 private float moveZ;

 void Start () {
     
 }
 
 void FixedUpdate () {

     rbody = GetComponent<Rigidbody>();
     canWalk = GetComponent<CanWalk>();
     switchSys = GetComponent<SwitchSystem>();
     animCtrl = GetComponent<AnimationController>();

     if (canWalk.CanMove)
     {
         if (!invertVertical) {inputV = Input.GetAxis("Vertical");}
         if (invertVertical) {inputV = -Input.GetAxis("Vertical");}

         if (!Input.GetKey(runButton) && !Input.GetKey(crowtchButton))
         {moveZ = inputV * speed * Time.fixedDeltaTime;}
         if (Input.GetKey(runButton) && !Input.GetKey(crowtchButton))
         {moveZ = inputV * speed * speedMultiplier * Time.fixedDeltaTime;}
         if (Input.GetKey(crowtchButton) && !Input.GetKey(runButton))
         {moveZ = inputV * speed / speedDivisor * Time.fixedDeltaTime;}
         if (Input.GetKey(crowtchButton) && Input.GetKey(runButton))
         {moveZ = inputV * speed * Time.fixedDeltaTime;}

         //Forward - invert backward
         if (inputV >= 0 && !switchSys.Switch_1_2)
         {rbody.AddForce(camTransform.forward * moveZ * Time.fixedDeltaTime, ForceMode.Force);}

         if (inputV >= 0 && switchSys.Switch_1_2)
         {rbody.AddForce(transform.forward * moveZ * Time.fixedDeltaTime, ForceMode.Force);}
             
         //Backward - invert forward
         if (inputV <= 0 && !switchSys.Switch_1_2)
         {rbody.AddForce(camTransform.forward * moveZ * Time.fixedDeltaTime, ForceMode.Force);}

         if (inputV <= 0 && switchSys.Switch_1_2)
         {rbody.AddForce(transform.forward * moveZ * Time.fixedDeltaTime, ForceMode.Force);}
     }
 }

But I can't stop my player sliding 'till some secs after I've released the walk key, I mean... Not without compromising all the walking system, be it with physics materials on the player, be it with physics magerials in the ground... I just can't! I need help! And that's for yesterday!