Search for special characters

Elastic Stack Elasticsearch
5

I have used below custom analyzer

PUT my_index
{
  "settings": {
    "index": {
      "analysis": {
        "analyzer": {
          "custom_analyzer": {
            "type": "custom",
            "tokenizer": "my_tokenizer"
          }
        },
        "tokenizer": {
          "my_tokenizer": {
            "type": "ngram",
            "min_gram": 1,
            "max_gram": 10
          }
        }
      }
    }
  },
  "mappings": {
    "doc": {
      "properties": {
        "my_field": {
          "type": "text",
          "analyzer": "custom_analyzer",
          "fields": {
            "keyword": {
              "ignore_above": 256,
              "type": "keyword"
            }
          }
        }
      }
    }
  }
}

PUT my_index/doc/2 
{
  "my_field":"$title123.txt"
}

PUT my_index/doc/1
{
  "my_field":"$titan@123#.txt"
}

Here special character search is working fine but if i search for titan i'm getting both the documents (my_field with title in it) which is irrelevant search