I have two questions regarding sidechain.
Q1. Do we need specific technology stack to create sidechain ?
Q2. Can any public blokchain can be use for sidechain ? also how can i use sidechain with Ethereum.
Plasma MVP is a good start, to create side chains of Ethereum. There is already a prototype by OmiseGo.
A lot of implementations are still experimental. It's not the easiest thing to do. Some people use State Channels, some create Plasma Chains, and then there are some others that use non-blockchain based implementations and just compute using standard languages.
Here are some built out code examples of each:
State Channels: https://github.com/SpankChain/general-state-channels
Plasma Chain: https://github.com/LayerXcom/plasma-mvp-vyper
Private Function Contracts: https://github.com/enigmampc/secret-contracts
So to answer your questions...
There is no standard technology stack
That is still to be determined, but I don't see why you could not use another blockchain platform as a sidechain.